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The American Naval Planning Section London

Published under the direction of The Hon. Edwin Denby, Secretary of the Navy

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American Naval Planning London cover image.


Publication Number 7


Published under the direction of
The Hon. EDWIN DENBY, Secretary of the Navy






Capt. N. C. Twining, United States Navy Frontispiece.
Capt. F. H. Schofield, United States Navy Facing frontispiece.
North Sea barrage 139
Capt. Luke McNamee, United States Navy 221
Capt. Dudley W. Knox, United States Navy 290
Capt. H. E. Yarnell, United States Navy 294
United States naval headquarters, London, England 311
Col. R. H. Dunlap, United States Marine Corps 331
Allied conference on Mediterranean mine laying 384
Col. Louis McCarty Little, United States Marine Corps 412
Charts 1-8 In pocket.




This monograph is virtually a reproduction of the formal records of the American Planning Section in London during the Great War, presented in numbered memoranda from 1 to 71, inclusive. Memoranda Nos. 21 and 67 have been omitted as being inappropriate for publication at this time.

Before December, 1917, all strategic planning for the American Navy was done by a section of the Office of Naval Operations in Washington. Admiral Suns urged the need of a Planning Section at his headquarters in London, where comprehensive and timely information was more available; not only of the activities of American Forces, but of the Allied Navies and of the enemy.

A visit to England during November, 1917, by Admiral Benson, Chief of Naval Operations, coincided with a reorganization of the British Admiralty, which included, as a result of war experience, magnification of the function of strategic planning by their War Staff. Decision was then reached to form an American Planning Section at the London headquarters of the Commander, U. S. Naval Forces Operating in European Waters, with the idea of cooperating more closely with the British and other Allied plan makers. Up to that time the naval strategy of the Allies often appeared to lack coordination and to be formulated primarily by men so burdened with pressing administrative details as to prevent them from giving due attention to broad plans. It was intended that the new arrangements should correct these defects.

The function of the Planning Section corresponded closely to that of similar units of organization in large businesses and in armies. Its work was removed from current administration, yet necessarily required constant information of the progress of events. It comprehended a broad survey of the course of the war as a whole, as well as a more detailed consideration of the important lesser aspects.

From an examination of these records of the American London Planning Section, together with its history contained in Memorandum No. 71, prepared soon after the conclusion of the war, it is evident that the influence of the Section upon the general naval campaign was constructive, comprehensive, and important.

D. W. Knox,
Captain (Retired), U. S. Navy,
Officer in Charge, Office of Naval Records
and Library; and Historical Section.



Memorandum No. 1.
Submitted 31 December, 1917.


(See Map No. 1, “The North Sea,”)


We have thought that it would assist us in the study of the barrage to have in mind clearly a statement of the mission of the barrage. After study and discussion the following mission has been accepted by all concerned:


To close the northern exit from the North Sea to submarines and raiders with the maximum completeness in the minimum time.

The way of accomplishing the mission is made up of several factors which, for the sake of clearness, may be discussed separately. First, then, let us consider the position of the barrage:


It is unnecessary to consider all the data which led originally to the selection of the Aberdeen-Ekersund line. It is sufficient to note that this line was at the time of its selection believed by both the British and American naval staffs to be the most acceptable position.

The second position considered in this memorandum is the one now proposed by the British Admiralty and accepted in principle by the Navy Department. There are many factors pro and con that entered into a choice as between the two positions, but of these a single factor controlled, viz, that the new position is deemed best by the grand fleet, upon which will rest the responsibility for the support and patrol of the barrage. The new position gives greater freedom of movement and greater ease of support to surface vessels, while it imposes corresponding difficulties upon the operations of enemy surface vessels. The change in position accepts the handicap of an average increase in depth of water about 15 fathoms. This handicap


might be considered serious were it not for the fact that the whole plan of the barrage is based upon the assumption that an effective mine field can be laid in 1,000 feet of water. If this assumption be true, then whether a portion of the mine field be in 40 or in 60 fathoms of water is not material, except as the change of plan introduces delay. If the assumption be not true, then the barrage is doomed to partial failure anyway.

It will be noted that the original line extended from mainland to mainland, while the new line extends from island to island and has in it passages completely navigable to submarines. This condition is, in our opinion, undesirable. We believe it wrong to accept a plan that provides in advance a way by which the plan may be defeated. This point will be discussed more fully when the character of the barrage is considered.


The proposed character of the barrage docs not provide for the full accomplishment of the mission. The proposed barrage will not close the northern exit from the North Sea, because—

(a) The barrage is not complete in a vertical plane in Areas B and C.

(b) The barrage is not deep enough.

(c) The Pentland Firth is open.

(d) The waters east of the Orkney Islands, for a distance of miles, are open.

(e) Patrol vessels on the surface are not sufficiently effective in barring passage to submarines, as witness the Straits of Dover.

The barrage is to be a great effort. It is our opinion that nothing short of a sound design will justify the effort.

The requirements of a sound design are the extension of the barrage complete in the vertical plane from coast to coast. If it be impracticable to carry the barrage up to the Orkneys, and to close the Pentland Firth, then the western end of the barrage should turn south to the Aberdeen Promontory.

The necessity for an opening in the surface barrage is recognized, but it is held that this opening should be in the surface barrage only, and that the deep barrage should be widened so that the difficulties of navigating the opening submerged may be practically prohibitive. Deep mines should cover for a considerable distance all approaches to the barrage opening.

The Norwegian coast presents special difficulties both in mining and patrol, but all of these difficulties will be greatly reduced by carrying the surface barrage up to the 3-mile limit. It will then be practicable to concentrate the strength of the patrol in the very near vicinity of Norwegian territorial waters.


The deep barrage in Norwegian waters should be extended so as to porcupine the coast both north and south of the surface barrage for a considerable distance. The submarine must be taught to fear all Norwegian territorial waters.

The above points concerning the character of the barrage arc points to which we attach great importance.


British experiments indicate that a length of antennae greater than 70 feet will not assure the destruction or disablement of an enemy submarine. This length requires three lines of mines in the vertical plane. Three lines permit the vertical barrage to be extended vertically to a depth of 235 feet. It is essential that the upper tier of mines have antennae of such length that vessels traveling on the surface may not escape, otherwise vessels might escape by the simple plan of making the passage on the surface in Area A. The necessity for short antennae is not so pronounced for the deeper mines, as the probability that submarines may make contact with the upper end of the deep antennae is much less than it is in the case of the shallow mines. The length of the antennae is related directly to the vertical width of the barrage, as follows:

(1) Three 70-foot antennae cover 235 feet.

(2) Three 100-foot antennae cover 325 feet.

(3) One 70-foot and two 100-foot antennae cover 295 feet.

Add 25 feet to each of the above depths and get the prohibited vertical zone for submarines.

We are of the opinion that the third combination should be used, as this combination provides for destruction on the surface and for reasonable certainty of destruction up to 300 feet submergence.


While the sequence of laying the mines is an operating matter, it seems desirable that the situation on the Norwegian coast be cleared up by laying the fields there as early as possible.

In Area A it may be desirable to lay the southern system first and to lay all deep mines before any shallow mines are laid.

Tentative Decisions.

1. To accept the new position of the barrage as outlined by the British Admiralty.

2. To urge that the barrage be complete in the vertical plane from coast to coast, except an opening in the surface barrage at the western end and in Norwegian territorial waters.

3. To carry the barrage to a depth of 295 feet.


4. To have surface mines fitted with 70-foot antenna; and other mines with 100-foot antennae.

5. To urge that deep mine fields be laid at numerous points on the Norwegian coast.

6. To urge that all approaches to barrage openings be mined with deep mine fields for a considerable distance, so as to make the navigation of these openings by submerged vessels as hazardous as possible.

(See British comment in Memorandum No. 3.)

Comment of British Admiralty.

A. Concur.

B. It is considered this assumption is true as far as can be judged with the knowledge in our possession.

The question as to the greatest depth to which the enemy submarines may be expected to dive was discussed with our submarine experts when the depth of the barrage was decided on.

The matter has been again discussed with them since the receipt of your memorandum and they confirm their former opinion that submarines will not of their own free will dive to a depth exceeding 200 feet.

To dive under the barrage the submarines would have to dive to 240 feet in the American mine field and to 215 feet in the British mine field, measuring to the bottom of the boat, which is the German practice.

It is the considered opinion of the submarine experts that it is of more importance to effectively mine from the surface to 200 feet rather than to mine deeper with a loss of efficiency down to 200 feet.

A question which must be taken into account is whether the explosion of a charge at a depth of 200 feet has a greater radius of destruction than a similar charge at a depth of 70 feet.

Opinions differ much on this point and without direct proof, which is difficult to obtain, it is considered the effect must be assumed to be equal.

A point which requires careful consideration is whether the American mine as now being constructed will withstand the external pressure to which it would be subjected if laid at 300 feet.

The possibility of having to lay mines at 300 feet has been taken into consideration in future orders of British mines.

Taking the above points into consideration, it is requested that you will put forward any proposals you may wish to make regarding the length of the antennae.

C. The stopping power of a mine barrage such as we propose to lay should not be overrated.


It is considered that if we relied on any mine barrage across such a great width to entirely stop submarines passing out of the North Sea our hopes would be foredoomed to failure, at any rate until the barrage had become very thick.

It is the patrol craft, armed with various antisubmarine devices, on which we must rely to actually kill the submarines.

Now, the efficiency of the patrol depends on its intensity, and it is on the mine field that we rely to give us this intensity.

The introduction of the “Acoustic mine” may, and we hope will, give us an instrument which will enable us to absolutely deny large areas to submarines unless they accept the probability of almost certain destruction.

The acoustic mine is not yet a fait accompli and therefore we can not base our plans on it.

Assuming that we are correct in considering the mine field only as an accessory to the patrol, we must arrange the mine fields to that end.

When looking at the plan of the Northern Barrage it immediately occurs to one, Why not extend the surface mine field right up to the Norwegian coast?

Until we have proved the efficiency of the American mine field we must look upon it as a bluff.

It is not suggested that the American mines will not be efficient, but only whether any system of existing mines will deny an area 150 miles in width to submarines.

We notify an area 150 miles in width as dangerous and hope that the enemy submarines will be diverted into the areas on each side where our patrol craft can deal with them.

If we attempt to put the bluff too high, which it is considered would be the case if we mined the eastern area up to the surface, there would be a chance of forcing the submarines to pass through the mine field, which they might find they could do without prohibitive loss. We should then be faced with the problem of patrolling the whole area between Orkneys and Norway—a task beyond our resources.

By the end of the summer the mine fields in the notified area will, it is hoped, be so dense as to make the danger of passing through them prohibitive, in which case we could then mine the eastern area up to the surface.

It would be desirable to do this, if possible, before next winter, as our patrol craft will find it next to impossible to efficiently patrol the eastern area during the stormy winter days with long nights.

D.     (a) The reason for not making it complete in Areas B and C has been explained under C.

        (b) Already discussed.


(c) The navigation of the Pentland Firth by submarines when diving is not considered to be a practicable proposition. Patrol craft should prevent submarines passing through it on the surface. Also, as already explained, the patrol areas thoroughly cover the approaches to the Firth, and as it is on the patrol craft we rely to destroy the submarine the fact that it is not covered by the mine field is not considered to be of vital importance. It is clearly recognized, however, that once the barrage has one or more systems completed right across, our subsequent mine laying must be adjusted to meet any new tactics on the part of the enemy. It may for instance be necessary to continue the deep mine field down to the coast of Scotland or to mine an area to cover the western end of the Pentland Firth.

(d) The patrol craft in the Straits of Dover are not at present fitted with up-to-date hydrophone gear, nor are strong tidal waters, such as the Straits of Dover, suitable for hunting with the fish hydrophone.

The efficiency of the patrols on the Northern Barrage should not, for the above reasons, be based on results obtained at Dover up to the present time.

Submitted: Question whether the barrage should be completed on the surface up to the Norwegian coast.

The American idea of having a surface mine barrage from the Orkneys to Shetlands is presumably based on the assumption that a mine field 220 miles in length can be made so effective that it will stop submarines passing through it.

The experience of the war, it is claimed, does not bear out this assumption.

Neither do we yet know whether the American mine is efficient.

When the design of the barrage was originally considered, it was estimated that three lines of mines at each depth would be required to make it efficient.

Now, three lines of mines at each depth will not be in place until well on in the summer, even if there are no more delays than we know of at present.

Hence the mine barrage can not be considered really effective until later on in the summer, and therefore we should not attach too much importance to it.

Now, if the above assumption is correct, we should almost certainty create a situation we could not deal with if we followed the American suggestion to mine up to the surface right across, for the following reasons:

(a) The submarines would break through the mine field without prohibitive loss.


(b) We should then be forced to patrol the whole area between Orkneys and Norway with fish hydrophone vessels. We have not sufficient craft to do this.

In the British plan the patrol vessels, with up-to-date hunting gear, are looked upon as the primary means of stopping the submarines, and the mine fields are only laid with two objects:

(a) By means of the notified area to bluff the submarines into using channels which are sufficiently narrow to allow of them being efficiently patrolled.

(b) The deep mine fields to help the patrol craft to kill the submarine.

It is submitted that, re Admiral Sims’s letter A:

(а) It is first necessary to see whether the submarines avoid the notified area. If they do not, it will be necessary to go on strengthening the notified area until they do avoid it.

(b) Before committing ourselves to mining the whole area up to the surface it is necessary to find out whether the American mine is efficient.

By the end of the summer the mine barrage should be sufficiently thick to make the passage of submarines through it prohibitive, and it will probably be desirable to continue the barrage up to the surface so as to reduce our patrols on the Norwegian coast to a minimum during the winter months when the weather is bad and the nights long.

It is considered by submarine experts that it is of infinitely more importance to make the barrage efficient down to 200 feet than to have a thinner mine field down to 300 feet.

3. As the Americans are mainly responsible for the center (notified) area it is considered they should have as much latitude as possible, and it is therefore suggested that the proposal to make the length of the antennae in the lower lines 100 feet should be concurred in.

This should only be done, however, if it is quite certain that the American mines can withstand the pressure at 300 feet.

4. When the main lines of the barrage have been completed the situation should be reviewed and further mine fields laid as proposed by the American officers where experience shows them to be necessary.

5. It is not considered essential to have the bottom of the barrage at the same depth right across. To extend the mine field downward in the case of the American mines only necessitates lengthening the antennae, whereas in the British mine fields it entails laying extra lines of mines.

As already stated, it is considered of much more importance to make the mine field effective down to 200 feet before extending the


mine field lower, and in the case of the British fields the deeper mines should not be laid until the present barrage is completed.

There does not appear to be any reason, however, why this should prevent the American mine field being extended downward.

Re Admiral Sims’s letter B:

1. It is considered the areas allocated to each country should remain as at present until it is seen what progress is made, viz:

British mines to be laid in Areas B and C.

American mines to be laid in Area A.

Should it be desired at a later date to mine Area B (western area) up to the surface with American mines, it could be done with the ordinary sinkers and mooring ropes, e. g., those similar to the ones in the center Area A.

To mine the eastern area up to the surface with American mines will require special long mooring ropes.

It is suggested, therefore, that the principle of the possibility of having to mine the eastern area up to the surface at a later date be accepted, and that the United States be asked on the completion of the mining of the center area with three systems to have sufficient sinkers with long mooring ropes ready to lay two lines of surface mines across that area.

Note.—The British mooring ropes provided for the eastern area are of a sufficient length to enable surface mines to be laid in that area should it be desired later.

3. Propose to inform the United States that the necessary navigational buoys and other marks are being provided by us for all mine fields.

[Extracts from Memorandum No. 71, “ History of Planning Section.”]

MEMORANDA NOS. 1 (31 DECEMBER, 1917), 3 (5 JANUARY, 1918), 17 (12 MARCH), 35 (11 JUNE), 42 (30 JULY), 43 (21 AUGUST), 51A (18 SEPTEMBER).

Subject: “Northern Mine Barrage."

From its organization the Planning Section was thoroughly convinced of the desirability of completing the barrage at an early date according to a design which would render the passage of submarines north about as hazardous as practicable.

Believing that the speedy completion of an effective barrage required agreement in advance upon a plan by the two navies which had jointly undertaken the project, frequent discussions and conferences were held with British officials. These developed important differences of opinion as to the general characteristics of the barrage, repeated efforts were made to reconcile these differences and to reduce to writing a concrete plan which would be acceptable to both navies. These efforts met with failure in so far as formal agreement upon a written plan was concerned, the British apparently desiring to reserve the privilege of altering the plan when expediency so dictated. They were probably influenced to adopt this attitude by the intentions (not then disclosed) to undertake extensive mining operations in “the Bight,” and at


Dover, which might interfere with any agreements they made with respect to the Northern Barrage. Possibly some skepticism also existed as to the ability of the Americans to execute satisfactorily their part of the project. Doubt as to the practicability of the barrage, as well as to its strategic importance, was frequently manifested by many high British officials, notably the Commander in Chief Grand Fleet, under whose general direction the laying operations and their protection were placed. This attitude was reflected in the Deputy Chief of Naval Staff, whose department in the Admiralty handled fleet affairs. It was upon the recommendation of the Commander in Chief that the position of the barrage was moved about 50 miles northward, placing the American Section in depths of water somewhat deeper than the original position. This incident alone put back American preparations about three weeks. It became known in about September, 1918, that the hostility of the Commander in Chief to the barrage was caused in large measure by the interference that the barrage would cause to the weekly Norwegian convoy, for the protection of which the Commander in Chief was held responsible.

The British Assistant Chief of Naval Staff was hostile to the barrage, apparently because of the probable influence which it would have to reduce the number of vessels available for convoys, for which duty he was primarily responsible.

For similar reasons, affecting their own job, practically every influential British official afloat and ashore was opposed to the barrage, except the British Plans Division.

This situation caused the American Planning Section constantly to urge orally expedition in the completion of the barrage, and to emphasize its great importance in the above memoranda, as well as in other papers upon more general subjects.

It is believed that the influence of this Section, exerted so constantly, considerably advanced the completion of the barrage. But for the lack of a proper agreement in the early stages of the project, and for the opposition of British officials, it is probable that the barrage might have become effective in the early summer of 1918.


Memorandum No. 2.


2 January, 1918.


The cablegram from Admiral Benson which expressed his desire that a Planning Section be organized in London stated as follows:


From: Admiral Benson.

To: Navy Department.

From my observation and after careful consideration, I believe that plans satisfactory to both countries can not be developed until we virtually establish a strict Planning Section for joint operations here (in London), in order that the personnel therein may be in a position to obtain latest British and allied information and to urge as joint plans such plans as our estimates and policy may indicate. This notion appears to be all the more necessary considering the fact that any offensive operations which we may undertake must be in conjunction with British forces and must be from bases established or occupied within British territorial waters. The officers detailed for this duty should come here fully imbued with our national and naval policy and ideas. Then, with intimate knowledge which they can obtain here from data available, actual disposition of allied forces, the reason therefor, they will be in a position to urge upon British any plans that promise satisfactory results.

(Signed) Benson.

Note.—Above cablegram was dated November 19, 1917.

In conversation with the First Sea Lord on New Year’s Day, he expressed the opinion that one of the Planning Section might be attached to the staff of Rear Admiral Keys at Dover; that another might be detailed in the Material Section of the Admiralty; and that the third officer might possibly be in the Operations Section of the Admiralty. The First Sea Lord offered these suggestions as tentative only, but seemed to dwell with some insistence on the Dover detail.

The proposed arrangement is not at all in accord with the expressed ideas of Admiral Benson and would but serve to nullify our usefulness as a Planning Section.

It is therefore proposed that it be pointed out to the First Sea Lord that the duties of the Planning Section must necessarily be more general. The United States is now involved in this war to an enormous degree. The naval vessels, and the troops on this side of the


water, are no correct measure of our participation in the war. Loans to the Allies, aggregating seven billion dollars, are being made with prospect of further loans. Our entire military effort is by way of the sea. We are intensely concerned in the measures taken to drive the Germans from the sea and in the measures taken to handle shipping at sea.

It is therefore appropriate that the Planning Section of Admiral Sims’s staff shall be free to consider those questions that seem to him and to the members of the section most urgent.

It appears to us that the principle that should govern our relations with the Admiralty is: The privileges of the Admiralty with complete freedom of action so far as the Admiralty is concerned.

These privileges and this freedom of action are essential if the Planning Section is to attain its maximum usefulness to our joint cause.

In presenting to the First Sea Lord such of these ideas as may be approved, we recommend that emphasis be placed upon our keen desire to be of the maximum possible usefulness to our joint cause.

It appears to us that we can be of most use if we work as a unit— all of us—considering, as a rule, the same subject simultaneously.

We think it desirable that we keep a continuous general estimate of the naval situation.

We think that the following special subjects should be studied by us very carefully at as early a date as possible:

(1) The Northern Barrage.

(2) The English Channel.

(3) The Straits of Otranto.

(4) The tactics of contact with submarines.

(5) The convoy system.

(6) Cooperation of United States naval forces and naval forces of the Allies.

(7) A joint naval doctrine.

Other subjects will undoubtedly present themselves faster than we can consider them, but the above illustrates the lines along which we believe our greatest usefulness lies.


Memorandum No. 3.


5 January, 1918.


On January 4 the Planning Section discussed with the British Admiralty Planning Section our memorandum regarding the Northern Barrage, which was submitted on January 1, 1918.

Captain Pound stated that his Planning Section did not consider that it was necessary to carry the barrage to a vertical depth of 300 feet nor to close the ends of the barrage by a surface barrage. He stated that he was preparing a typewritten exposition of his views on the subject. He stated further that he saw no reason whatever why the American part of the barrage should not be laid down in accordance with the principles set forth in our memorandum of January 1. He said also that the British Admiralty would be prepared to extend their barrage to a greater depth if found necessary and to mine the surface should that become desirable.

We are informed by Commander Murfin that our memorandum of January 1 was shown to Captain Lockhart Leith and by him accepted in toto as sound.

Pending the decision of all points regarding cooperation in the laying of the mine barrage, we think it very desirable that the following information which bears upon the manufacture of mines should be transmitted to the Navy Department without delay:

The American Planning Section, plus Commander Murfin and Lieut. Commander Schuyler, recommend the following characteristics of mine barrage in Area A:

Length of antennae for upper mines, 70 feet from mine to top of upper float.

For all other mines, 100 feet.

Three levels of mines.

Depth of upper float of upper level of mines below surface not more than 8 feet.

Depth of lower tier of mines below surface, 298 feet.

The above characteristics of American mine field have been discussed with Admiralty Planning Division and accepted.

British propose placing their deepest mines 180 feet below surface, but will be prepared to extend barrage downward if found neces-


sary. The desirability of a deeper barrage has been urgently discussed with Admiralty Planning Section. Suggest department express its opinion that British barrage be deeper and that it be a complete barrage from coast to coast, rather than a barrage including many miles of deep mine fields only.

We recommend that strong pressure be brought to bear to have the barrage include the characteristics outlined in our memorandum of January 1, 1918.


Memorandum No. 4.


4 February, 1918.



The following notes are based upon the best experience to date. They have been prepared by the Planning Section in collaboration with Capt. R. H. Leigh, United States Navy. Sources are—

(а) A limited experience in hunting enemy submarines.

(b) Reports and suggestions from officers engaged in antisubmarine warfare.

(c) Experimental work with friendly submarines.

(d) Deductions from tactical studies on the maneuver board.

It is realized fully that the operation of hunting submarines by sound is too new to justify hard-and-fast rules of conduct, yet better results can be obtained at the start if the rules already tentatively arrived at, and based upon experience to date, are accepted and followed than if each hunting unit determines its own rules without reference to the experience of others.

As hunting units gain experience, it is proposed to have conferences from time to time at the Admiralty of officers commanding units in various areas, so that these officers, by the exchange of ideas and by discussion, may assist in the formulation and development of the tactics most suitable for the hunting of submarines by sound-detection devices. Meanwhile all officers are cordially urged to assist in this important work by submitting criticisms of methods of hunting and suggested improvements both in methods and in material. We want the service of the best brains and energy available for this important work.


No description of the instruments used in submarine detection by hunting units will be attempted here, as suitable descriptive pamphlets have been—or will be—issued. The instruments will simply be enumerated and a brief statement given of their capabilities.

1. The fish is for use under way with engines stopped. Can be used when anchored in a tideway except for about one hour on each side slack water. Can be towed at any reasonable speed; can hear


submarines about 4 miles when engines of towing vessel are stopped; with amplifier this range is increased. Indicates direction of sound with a probable error of 5° to 10° if sound is distant. If sound is close aboard, directional quality disappears. Requires about three minutes after engines are stopped for an observation. Is short-lived on account of multiple wire cable.

2. The K. tube is for use when drifting, coasting (head reaching slowly), with engines stopped, or when anchored in a tideway. No towing model is available as yet. Instrument must be streamed for each observation and then taken on board before getting under way again.

Can hear submarines as follows:

Speed of submerged submarine: Distance (yards).
0.6 knot 2,500-3,000
2 knots 8,000-10,000
4 knots 15,000-20,000

Indicates direction of sound with probable error of 5° to 10°. If sound is very close aboard, directional quality disappears.

Requires five to eight minutes from signal to stop engines until observation is obtained and instrument is on board again ready for going ahead.

Instrument is very simple, sturdy, and reliable.

Efficiency is not interfered with by water noises of the surface in rough weather.

3. The S. C. tube is for use when stopped, when drifting, or when head reaching slowly, with engines stopped. Instrument is always in place ready for use.

Can hear submarines as follows, depending on state of sea and speed of vessel heard:

Speed of submerged submarine: Distance (yards).
0.6 knot 500-700
2 knots 1,200-2,500
4 knots 2,000-4,000

Indicates direction of sound with probable error of less than 5° at all ranges.

Requires about two minutes from signal to stop engines to get observation and be ready to go ahead again.

Instrument is simple and sturdy—never gets out of order.

Efficiency is interfered with by water noises and by excessive motion of vessel.

Not suitable for use in rough weather.

4. The trailing wire is for towing at slow speeds to detect a submerged submarine and especially a submarine resting on the bottom. Contact of the wire with the submarine gives instant indication of the contact.



All listening vessels should be organized into units of three vessels each, to be known hereafter as hunting units. The vessels of each unit will habitually operate in tactical support of each other They should be sufficiently well armed—

(a) To protect themselves against the gun attack of a submarine.

(b) To attack successfully a submerged submarine when it has been located.

(c) To prevent a submerged submarine from coming to the surface and escaping by superior speed.

Note.—Hunting units operating in areas exposed to the raids of enemy surface vessels may require supporting vessels.

It is desirable that one vessel of each hunting unit be powerful enough and fast enough to cope with an enemy submarine on the surface. Whenever the hunting unit is of a class of vessels that can not meet the requirements (a), (b), and (c) above, then a special vessel, P-boat or destroyer, should be added to the unit as a support. When the listening devices are developed so that they can be used efficiently on P-boats and destroyers, these vessels, when assigned to hunting units, should replace one of the other listening vessels, so that the units shall consist of three instead of four vessels.

It is essential that the organization of units shall be permanent, so that the same vessels shall always work together. This will permit the development of real team work in tactics and in signals. The utmost skill in operation can be obtained only by continuity of association of ships and personnel.

In the matter of recognition of services rendered, it should be a principle that all vessels of a unit that actually participate in an operation shall share equally in the honor of success.

Tactics of Submarine if Pursued.

The principal cases of submarine pursuit will be—

(1) Daylight—on soundings.

(2) Daylight—off soundings.

(3) Night—on soundings.

(4) Night—off soundings.

During daylight in crowded waters the submarine operates, as a rule, submerged. If pursued on soundings during daylight while submerged, the submarine may—

(a) Attempt to escape by proceeding at maximum speed.

(b) Attempt to escape by proceeding at slow speed—say 2 to 3 knots.


(c) Attempt to escape by resting on the bottom. Submarine will probably not attempt this operation in water more than 30 or 35 fathoms deep, and will always seek bottom free from rocks and other dangers to bottoming.

(d) If near bottoming ground, may attempt to escape by proceeding slowly, stopping and balancing occasionally to listen, or stopping synchronously with the hunting unit.

(e) May anchor submerged—submarines frequently rest on the bottom; when so doing they are apt to drift slowly.

Note.—A submarine proceeding submerged can probably continue under way as follows:

Speed 1 1/2 to 2 knots 60
Speed 5 knots 12
Speed 7 knots 3
Speed 8 to 9 knots 1 1/2
Speed 10 to 11 knots 1

These rough estimates are based on the capabilities of the average submarine. Later types of enemy submarines have greater submerged radius. The surface speed of enemy submarine varies in different classes from 10 to 18 knots.

At night submarines are usually to be found on the surface charging batteries, cruising to new stations, or operating. One of the first concerns of a submarine is to keep its battery fully charged. In crowded waters the submarine finds it too dangerous to charge batteries except at night.

When operating far offshore it has much more latitude, and doubtless charges its batteries while cruising on the lookout for victims. When on the surface a submarine will probably have a little of the upper deck showing. It may be stationary or under way, depending on circumstances. If under way it can submerge in from 30 to 40 seconds; if stationary time to get under way must be added.

If discovered at night on the surface the submarine may—

(a) Attempt to escape on the surface by use of superior speed.

(b) Attempt to escape by submerging. If submarine submerges, tactics of escape will be similar to daylight tactics.

The submarine’s chance of escape when off soundings are less than when on soundings because it has no refuge and must keep under way.

In every case of attempt at escape we must expect that the submarine will use every possible means to shake off pursuit. A good guide to measures to take in pursuit is to place one’s self in the position of the pursued submarine and decide upon what steps would be taken to escape under the circumstances. It is, of course, necessary to assume that the submerged submarine can hear pursuing vessels, and that it makes no noise when its engines and motors are stopped.



The tactics of submarine hunting by sound may be divided into three stages :

(1) Search.

(2) Pursuit.

(3) Attack.


Information of the approximate position of an enemy submarine may be gained by—

(a) Report from shore listening stations.

(b) Reports from directional wireless telegraph stations.

(c) S. O. S. calls.

(d) Reports from aircraft and vessels at sea or reports from coastal stations.

When reports of the above nature are received, hunting units will be designated to search the area near the reported position of the submarine. In the absence of such reports, the hunting unit will seek enemy submarines in areas or along routes assigned.

Three methods of search will be considered:

(1) Anchored patrol.

(2) Drifting patrol.

(3) Running patrol.

The anchored patrol may be used to establish a sound barrage along a line, or around an area in which an enemy submarine has bottomed.

Advantages are:

(а) Ease and certainty of maintenance of position.

(b) Each vessel knows bearing and distance of all other vessels of units at night or in thick weather.

(c) No necessity for using lights for position signals.

(d) Possibility of a continuous watch on all short-range listening equipment and, except at turn of tide, a continuous watch on other listening equipments.

Disadvantages are:

(a) Impracticable in rough sea.

(b) Probable delay in getting under way for pursuit.

(c) At slack water there is a period of about one hour when directional quality of all long-range listening devices disappears— this because fish and K tube do not remain on a constant heading.

(d) Loses submarine if it drifts along the bottom.

When anchored patrol is decided upon—

Use a hawser instead of chain for anchor cable, as handling chain betrays you to the submarine.

Be ready to slip instantly.


Keep the support under way always.

The best formation for anchored patrol is in line normal to the probable course of enemy submarines. In the case of a bottomed submarine the best formation is a triangle inclosing probable position of enemy submarine.

The drifting patrol may be used to establish a sound barrage along a line that shifts with the current, or around an area in which an enemy submarine is believed to be drifting. It is particularly applicable off soundings in an area where a submarine has been seen to submerge and within which the submarine must surely be.

The advantages are:

(a) No necessity for using lights.

Note.—Relative bearings can be ascertained by tapping a prearranged signal at specified times on vessel’s hull inside, below water line. Loudness of sounds will indicate approximate distances. Bearings within 3° to 5° of accuracy may be obtained by this method.

(b) Possibility of a continuous watch on all listening equipment, due to fact that own noises are not present to interfere.

(c) Enemy receives no sound warning from noises of hunting group.

Disadvantages are:

(a) Hunting unit will drift out of touch with a bottomed submarine.

Note.—Remedy by day is to anchor a buoy as a guide. In planting buoy, speed up engines to drown sound of buoy, anchor, and cable; or lower anchor by hand quietly.

(b) Submarine may attack with good chance of success.

(c) Difficult to maintain position.

Note.—Effort to regain position will betray presence of units. If all vessels move simultaneously one might continue out of sound range of the submarine, to convince submarine that area was clear.

Note.—In both the drifting and anchored patrol extreme caution is necessary to avoid making noises. Do not throw things about the deck or against the hull of the ship. Do not break up coal while drifting. Do not hammer, except when necessary, for position signals.

(d) Fish hydrophones may not be used.

(e) Engines have to be kept warmed up, thus causing noise.

The best formations for drifting patrol are the same as for anchored patrol.

The running patrol is for use in searching a large area for submarines under way. It should be used in going to and from station unless proceeding to intercept a reported submarine, when the running patrol need not be taken up until within the area of possible contact with the submarine reported.


The running patrol may sometimes be used in advance of, and out of sound of, a convoy, as a measure of protection.

In the running patrol vessels proceed on course assigned, stopping engines and auxiliaries for listening observation simultaneously at predetermined intervals. The efficient working of a running patrol requires that timepieces be kept in exact step.

The running patrol is particularly applicable for day use, as vessels are made safer from attack when under way, and if various other vessels are operating in the vicinity, these latter may be avoided, so as to prevent sound interference.

Advantages are:

(a) Covers a large area.

(b) Easy to maintain position.

(c) Engines ready for emergencies at all times.

Disadvantages are:

(a) Enemy submarines have opportunity to hear hunting unit.

Formation.—The best formation for a hunting unit of three vessels to take in running patrol is line abeam. This formation should be used in proceeding to the patrol area and while on patrol.

Support.—If the support is a destroyer or similar vessel, it should zigzag within supporting distance in rear of the listening vessels at a distance sufficiently great to prevent its noises from interfering with the sound detection of submarines.

Distance.—Distance between listening vessels is dependent on efficiency of listening equipment.

If sound radius is 3 miles, vessels may be stationed 4 miles apart; they should then stop to listen every 20 minutes.

If sound radius is 2 miles, vessels may be stationed 3 miles apart; they should then stop to listen every 15 minutes.

If sound radius is 1 1/2 miles, vessels may be stationed 2 miles apart; they should then stop to listen every 10 minutes.

If sound radius is 1 mile, vessels may be stationed 1 1/2 miles apart; they should then stop to listen every 8 minutes.


The pursuit of an enemy submarine by a hunting unit requires a thorough understanding of the game by all concerned. There must be teamwork in listening, signaling, and maneuvering. Each vessel of the unit should require practically no direction from the flag boat.

Each ship commander must be kept fully informed of all matters that bear upon the success of the pursuit. The commander of each unit is responsible for the development of the “team spirit” and “teamwork” of his group. He should hold frequent conferences of the officers of the unit while in port, for an interchange of ideas, for discussing improved methods, for eliminating causes of failure,


or lack of complete success in teamwork. He should propose situations and ask officers in turn for their decisions to meet the situations proposed, correcting decisions, and explaining corrections as necessary. It is an invaluable practice for the hunting unit commander and his subordinates to work out tactical problems on a maneuver board and to discuss each successive phase of each problem until they are all thoroughly conversant with likely situations and the ways of meeting them.

Once sound contact with a submarine has been made, nothing but bad weather should be accepted as legitimate reason for losing sound contact. The detection instruments already provided and about to be provided should enable a competent personnel to run the submarine down.

When a submarine is heard, the vessel hearing submarine reports immediately—

(1) The magnetic bearing.

(2) Estimated distance.

(3) Whether submarine is on surface or submerged; and heads toward submarine. Other vessels maneuver to take position at one-half mile distance, in line abeam of vessel that made sound contact. All vessels observe the silent interval of the pursuit, if not otherwise signaled by unit leader. The silent interval of the pursuit should be sufficiently frequent to prevent any possibility of—

(1) Submarine passing beyond hearing between silent intervals.

(2) The submarine being overrun between silent intervals.

Immediately upon the reporting of an enemy submarine, all vessels

must keep a specially sharp lookout for signals from the hunting unit leader. The hunting unit leader should keep plotted the bearing of the submarine from the leader, and the approximate relative positions of the vessels of the unit. The position of the submarine may be determined more accurately if the unit leader is given simultaneous bearings of the submarine by two or more vessels and if these bearings are plotted on cross-section paper on which has previously been plotted the relative positions of all vessels of the hunting unit. The hunting unit leader should keep all vessels of hunting unit informed of estimated position of submarine.

In moderately rough weather it is advisable to keep “weather gauge” of the submarine, as water noises interfere considerably when attempting to head into the sea, but are negligible when drifting or running before the sea.

In pursuing a submarine, assume its speed is 4 knots per hour, unless listener can give a good estimate of submarine’s speed by counting the number of revolutions of its propellers.

Overrunning a submerged submarine places the hunting unit at a distinct disadvantages, as noises astern can not be heard with any-


thing like the same efficiency as noises on the beam or ahead. Neither can the bearing of the noises heard be so accurately determined.

During the pursuit in line abeam, vessels of the hunting unit should close gradually to a distance of 400 yards, providing the submarine is heard clearly.

In the pursuit if enemy submarine attempts to synchronize use of his propellers with the hunting unit, so as to avoid danger of sound detection, one vessel of the unit should stop her engines a minute ahead of the other vessels so that it may begin its observations instantly the other vessels stop.

In inclosed or crowded waters it will be difficult to pursue a submerged submarine to exhaustion. It is therefore very essential so to maneuver as to bring about the attack as soon as possible after contact.

If during the pursuit sound contact is lost, the circumstances should indicate whether the submarine is beyond range of the listening devices, balancing, or bottoming; if balancing or bottoming is suspected, a judicious use of depth charges may cause a submarine to betray its position.


Preceding the attack vessels should have been so maneuvered as to close the submarine, but with the submarine still ahead should be in line abreast, distant not more than two cables apart.

The support should not close the attacking vessels in daytime until specifically so ordered, as the noise of the machinery of the support interferes too seriously with the tracking of the submarine. Time for attack should be chosen when the indications are that the submarine is on a steady course and when the submarine is as close aboard as it is practicable to get it without overrunning it. The signal for attack should immediately follow the expiration of a silent interval. Upon signal to attack all vessels should proceed at maximum speed, the center vessel toward the estimated position of the submarine, the flank vessels toward a position that will be 200 yards on either beam of the center vessel when it begins dropping depth charges. The center vessel should drop first depth charge 100 yards short of estimated position of submarine and successive depth charges as rapidly as possible, being careful not to drop any depth charge until the preceding one has exploded or until the vessel is beyond countermining distance of the preceding depth charge. The flank vessels should begin dropping depth charges immediately after the first depth charge of the center vessel has exploded, and successive depth charges according to the rule just laid down for the center vessel. All vessels during the depth-charge, attack should steer a course parallel to the course they were steering at the time the


attack was ordered, unless the submarine gives positive indication of its presence in another area.

Time for ordering the attack will depend entirely upon the judgment of the commander of the hunting unit, unless the submarine shows itself in position for attack, when the nearest vessel should attack immediately and without signal. Vessels should not expend all their depth charges in an attack that is guided by sound alone.

If during the pursuit touch is lost with the submarine, the commander of the hunting unit must determine upon his procedure, having in mind the capabilities of his various listening devices, the advantages and disadvantages of the various forms of patrol, and the probabilities as to what the submarine would do under the circumstances.



(1) See all instruments in working order.

(2) See that listeners arc trained in their duties.

(3) Unit commander assemble commanding officers and explain plans, then by question and answer and by instruction on maneuver board make certain that tactical plans are so thoroughly understood that no tactical signals will be necessary in pursuit except—

(a) Submarine heard.

(b) Bearing and distance.

(c) Stop and start.

(d) Attack.

(e) Course to be steered.

(4) Each commanding officer of ship assemble ship’s officers, petty officers, and listeners and instruct them in plans so that they will be able to work together as a team and each one will know exactly what to do under all conditions.

(5) Set all clocks by time signal.

(6) Determine and announce frequency and length of silent interval when on running patrol.

(7) Determine and announce frequency and length of silent interval in pursuit.


(1) As soon as clear of harbor, form line abeam. Unit leader in center; distance between vessels as predetermined, support zigzagging a predetermined distance astern.

(2) Proceed to station carrying on running patrol unless special circumstances make it necessary to arrive on station as soon as possible.



(1) Begin first silent interval on signal.

(2) Start and stop thereafter by clock time.

(3) Use only those instruments ordered.

(4) First vessel hearing submarine heads for it at once. Other vessels conform to the change of course, directing their movements to get in line abeam on new course at pursuit distance.

(5) All vessels at once take up frequency and length of silent interval previously described.


(1) Center vessel keeps submarine ahead. Right-flanked vessel keeps submarine on port bow. Left-flank vessel keeps submarine on starboard bow.

(2) Regulate speed so as not to overrun submarine previous to decision to attack.

(3) Flank vessels of pursuit line close gradually to 400 yards distance from center vessel.

(4) All vessels signal bearing and estimated distance of submarine at end of each silent interval.

(5) All vessels change course to conform to movements of submarine and requirements of subparagraphs (1) and (3) above, without signal. Guide on flag boat of pursuit line.

(6) All vessels keep sharpest possible lookout for submarine. If sighted, attack immediately.


(1) Get as close to submarine as possible and locate its position as accurately as possible.

(2) Begin attack at full speed, center vessel heading for last reported position of submarine; other vessels closing to 100 yards on center vessel, maintaining formation line abeam and taking up parallel course.

(3) Center vessel drops first depth charge 100 yards short of estimated position of submarine. Drops succeeding depth charges as rapidly as possible, avoiding danger of countermining.

(4) Flank vessels drop first depth charges immediately after first depth charge of center vessel has exploded and drop successive depth charges according to rule just laid down for center vessel.

(5) All vessels conserve a part of their depth charges unless attack is based upon “close aboard” sighting of the submarine.




10 January, 1918.


One of the most urgent problems of the hour is the immediate increase of tonnage to augment the supply of food and munitions. Actual sinkings by submarines do not give a true indication of actual losses in carrying capacity incident to submarine warfare. To the sinkings must be added:

(1) Vessels damaged by submarines.

(2) Vessels damaged in collisions incident to convoy operations and to running without lights.

(3) Losses in ton-miles per day due to convoy operations.

(4) Delays in port due to inadequate port facilities.

(5) Employment of merchant tonnage in naval operations.

All of these factors are cumulative and of such a serious nature as to demand the closest scrutiny to determine if it is not possible to reduce their unfavorable effect.

We have considered especially the employment of merchant tonnage as auxiliary cruisers. It is used for patrol and escort duties. It is in no sense at any time a reply to the submarine, but rather an additional target in each instance. The principal usefulness of merchant vessels as auxiliary cruisers is protection of convoys against raiders. There are no known raiders at sea now. The present situation requires that no move in the game be lost and that some risk be accepted if we are to continue the war. We therefore recommend the immediate acceptance as a principle of action: “The maximum possible employment of all auxiliary cruisers in the ocean transport of food and munitions for the support of the war.”


The following-named vessels of the Royal Navy appear to be employed in a manner not in harmony with the above principle:

Name. Gross tonnage. Name. Gross tonnage.
Teutonic 9,984 Arlanza 15,044
Columbella 8,292 Avoca 11,073
Alsatian 18,485 Ebro 8,480
Hildebrand 6,991 Almanzora 16,034
Orotava 5,980 Orcoma 11,571
Mantua 10,885 Orbita 15,678
Patia 6,103 Moldavia 9,500
Patuca 6,103 Himalaya 6,929
Virginian 10,757 Gloucestershire 8,124
Motagua 5,977 City of London 8,917
Changuinola 5,978 Princess 8,684
Edinburgh Castle 13,326 Morea 10,890
Armadale Castle 12,973 Knight Templar 7,175
Kildonan Castle 9,692 Mechanician ---- 
Otranto 12,124 Wyncote ---- 
Orvieto 12,130 Currigan Head ---- 
Ophir 6,942 Coronado ---- 
Calgarian 17,515 Bayano ---- 
Victorian 10,635 Discoverer ---- 
Macedonia 10,512    
Marmora 10,509 41 vessels 1400,000
Andea 15,620

1 Approximate.




11 January, 1918.

(See Map No. 2, “Entrance to the Baltic Sea.”)


Admiral Oliver, D. C. N. S., at the British Admiralty, requested through Captain Fuller, R. N., of the Admiralty Plans Division, that the American Planning Section consider the problem of the Great Belt. Later the details of the problem were communicated to the Planning Section orally and were assembled into the statement of the problem which follows.

The Planning Section considers it desirable to state that their method of solving a problem is to conclude as to the way of accomplishing the mission. They accept the mission imposed by the statement of the problem and thereafter give their exclusive attention to the accomplishment of that mission. In some problems the mission imposed may be unsound, but the problem solver is nevertheless bound to determine a way of accomplishing the mission.

Some observations have been appended to the solution transmitted herewith.


[Proposed by British Admiralty, 5 January, 1917.]

General situation: The war continues.

The Allies have succeeded in blocking the entrances to German North Sea ports, except Helgoland and the Belgian ports, denying exit of enemy submarines and surface vessels. The High Seas Fleet was behind the Elbe barrage when that barrage was completed and is unrestricted in its operations except by the Elbe barrage and by such additional measures as may be taken. Enemy submarine warfare continues by submarines passing through the Sound and the Belts and issuing from unblocked ports.

Special situation: The Allies decide to deny passage of enemy vessels into the North Sea through the Skagerrack.

Required: Estimate of the situation and plans to carry the above operations into effect.


Estimate of the Situation.

Mission.—To deny passage of enemy vessels in the North Sea through the Skagerrack.

Enemy Forces - Strength, Disposition, Probable Intentions.

Strength.—The enemy naval forces consist of approximately the following:

High Seas Fleet: Flanders—Continued.
  20 dreadnoughts.   6 T. B’s.
5 battle cruisers. 80 trawlers.
11 light cruisers. Unassigned:
2 mine-laying cruisers.   17 old battleships and coast
defense ships.
66 destroyers.
100 T. B.’s (organized as mine-sweeping divisions). 3 cruisers.
12 light cruisers.
45 trawlers. 38 mining vessels.
Flanders: 34 destroyers.
  14 destroyers. 44 T. B’s.
13 T. B.s. About 200 submarines, of which 30 are based in Flanders.
3 light cruisers.
42 destroyers.

We may assume:

(1) 40 submarines at seas from German ports.

(2) 45 U, U. B., and U. C. boats in the Mediterranean.

(3) 20 destroyers in Belgian ports.

(4) 20 U-boats based on Helgoland.

(5) 30 U. B. and U. C. boats based in Flanders.

We may assume all other enemy mobile naval forces as behind the barrages with no available exit to the North Sea except the Skagerrack.

The first move toward blocking operations will immediately force upon the enemy the consideration of the problem of keeping the Skagerrack open. If the blocking is complete as to the High Seas Fleet, and reasonably complete as to submarines, the Skagerrack problem immediately becomes one of first importance to the enemy. He now controls all approaches to the Baltic from the entrances to the Belts and Sound south. Blocking operations will compel him to advance his control as far north as possible. He can not afford to hold his barrage lines as at present, for then the High Seas Fleet could never hope to gain the open sea in condition for general action.

It is quite possible that the enemy may not plan any general engagement with the Grand Fleet and that he may desire to avoid precipitating such an engagement, but immediately that the High Seas Fleet is shut in the Baltic the great influence of the High Seas Fleet on allied operations in the North Sea disappears. The allied


fleets are then at liberty to close the Helgoland Bight and to guard the barrages of the North Sea ports. Further, the Allies may concentrate their forces to cover the single exit of the High Seas Fleet into the open sea. The enemy understanding this position quite as thoroughly as we do will be compelled to adopt simultaneously two courses of action:

(1) To clear the barrages of the North Sea ports.

(2) To secure to himself freedom of exit for all his forces through the Skagerrack.

By the terms of the problem we omit the consideration of (1) above and assume that the barrage is maintained. We have to consider (2). What does the enemy require for freedom of exit of all his forces through the Skagerrack?

As to submarines he requires that the Kattegat shall be free of mines and patrol craft and especially that Danish and Swedish territorial waters shall contain no submarine traps. He requires that submarines may gain the deep water of the Skagerrack without unusual risk.

As to the High Seas Fleet he requires for it an even greater degree of security in the Kattegat than for his submarines. How will he go about getting this security? There is but one answer to his situation, and that is to advance his barriers to the deep water of the Skagerrack. He would then be in touch with water across which no passive barrier could be erected and would secure to himself as much freedom of exit as possible without establishing a base in Norwegian waters.

Any barrier which the enemy may establish in the vicinity of the Skaw in order to be complete must extend into the waters of Denmark and Sweden. Under present conditions there is no doubt that he could bring sufficient pressure on those countries to cause them to mine their own waters in such a way as to join up with a German barrier outside of neutral waters. The northern barrier once in position, other mine fields in the Kattegat would be laid by the enemy in positions calculated to give tactical support to the necessary effort of his mobile forces in maintaining the barrier.

The Skaw is about 240 miles from Kiel and about 480 miles from Cromarty Firth. Whoever attempts to maintain a barrier at the Skaw must be ready to support it with capital ships and to give those ships the shelter of shore protection. Foreseeing such a necessity, it is probable that the enemy as soon as he becomes convinced that his North Sea ports are effectively blocked will occupy so much of Denmark as may be necessary to control absolutely the Belts and the Sound, the vicinity of his northern barrier, and an advanced anchorage for supporting vessels.


The enemy submarines at sea will necessarily be directed to ports other than North Sea ports of Germany. They may go to Helgoland, but the presumption of the problem is that they will return by way of the Skagerrack. It therefore becomes a matter of importance to arrange for them a proper reception. They will, so far as practicable, assist the enemy to hinder our operations.

The enemy is favored as late as the middle of March by the fact that ice may embarrass operations undertaken by us in narrow waters.

To summarize probable intentions of enemy, he will:

(1) Attempt to establish a mine barrier with suitable gates near the Skaw, requiring the participation of Denmark and Sweden or else violating the neutrality of their waters.

(2) He will occupy shore positions in sufficient force to control the northern approaches to the Belts and the Sound.

(3) He will probably occupy shore positions in the north of Jutland, so as to control his mine barriers and guard his supporting vessels.

(4) He will use every effort to keep the Kattegat completely within his control, occupying so much of Denmark as may be necessary and possibly forcing Sweden into the war.


The strength of our naval forces need not be enumerated here. It is sufficient to state that they are so far superior to enemy naval forces that he is unlikely to accept a general engagement until he has first induced a partial separation of our forces. The distribution of forces is as indicated in official publications. The nearest base is about 480 miles from the Skaw.

The decision to deny passage of enemy vessels (including submarines) into the North Sea through the Skagerrack compels at once that the operations to accomplish this mission shall be to the southward of the Skaw. The Skagerrack does not lend itself to mining operations, to net protection, or to any form of passive defense. It is true that the control of the shore would cover a certain area of water contiguous to the shore, but our mission requires that whatever steps are taken shall be effective from shore to shore.

Experience has shown that a surface patrol is not in itself a barrier to submarines, even though the tendency of the surface patrol is toward greater efficiency due to advances made in submarine detection apparatus and the increased skill of the personnel operating this apparatus. We are therefore obliged to resort to mine barriers—and possibly net barriers—and to supplement these by antisubmarine patrol and by a powerful support by surface vessels. The first


question to decide then in our measures is the position of the mine barriers. We have two cases to consider:

(1) Mine barriers protected by military as well as naval forces.

(2) Mine barriers protected by naval forces only.

From the investigation of the enemy situation it is evident that no permanency in barrier arrangements that will be effective against submarines can be attained except by the military protection of the shore ends of the barriers. Barriers may be placed anywhere in the Kattegat. The farther south they are placed the greater opportunity there is to establish successive barriers, while still retaining maneuvering room for supporting vessels. The most southerly position that may be considered accessible is across the channels on either side of Samso Island. Assuming no resistance from shore, this is probably the easiest place to close both the Great and Little Belts, but from the assumptions already made it is evident that we can not expect to maintain the position except by the occupation of Samso Island, Tuno, Tuno Knob, and Seiro Island. These positions are more remote from land attack and therefore, with a given defending force, should last longer than others farther south, as, for instance, the Kullen Peninsula position, which can be attacked by land from Siaelland.

The Sound remains to be closed by a barrier and the ends of that barrier to be protected from shore. If the barrier be placed in the narrow part of the channel north of Helsingor, both ends may be protected from Siaelland.

As a delaying operation we may consider it possible to close the Belts and the Sound by the occupation of Samso, Tuno, Tuno Knob, and Seiro Islands, and of land positions near Helsingor. The Sound is the weak point in this barrier, since the shore ends can not be made secure except by military operations on a large scale—probably beyond the capacity of available forces and facilities. But since the Sound will not accommodate vessels of over 24-feet draft it will be of decided advantage to close the Belts there by shutting in the High Seas Fleet. The continuous enlargement of mine fields in the vicinity of the Sound will compel the enemy to expose his surface craft or to accept a barrier of extreme danger to his submarines.

The position next north of the Samso Island position is the Siaelland-Odde-Heilm Island-Hasenore line. Heilm Island and Siaelland-Odde Peninsula, if securely held, would give the necessary support to the shore ends of the barrier. The line is easier to patrol than the Samso Island position, but the shore position at the eastern end is far less secure. The barrier might be considered as auxiliary to the Samso Island barrier, but would by itself offer less resistance than the Samso Island barrier. The treatment of the Sound would remain unchanged were this position adopted.


The Stamshead-Anholt-Morup Tange line may be considered as the most available barrier position in its vicinity. The occupation of Anholt would give the line strength in the center, but the ends would soon be exposed to attack from shore unless a large shore force supported the ends or unless large ships were used to cover the ends.

It is, of course, understood that the mission of enemy shore activities is to cover their surface craft while they break down our barriers. The enemy will naturally desire to compel our ships to work under his guns whenever possible, as this is a distinct advantage for him. It is, in fact, sound strategy when the question is considered by itself to arrange so that enemy ships will be provoked into fighting shore batteries. We should avoid such provocation so far as foresight will permit. The Anholt line would require above 7,000 American mines as against 4,500 for the Samso Sound barrier. One-third this number of mines will put one system across at either place.

The Anholt position offers less navigational dangers for patrolling vessels.

Laeso Island might be used as the center of a barrier still farther north. Here deeper water would be encountered, requiring more mines per mile for an antisubmarine barrier. The number of American mines required would be about 7,500 for three systems. There would be the usual difficulties regarding the ends, which, however, would be some distance from rail communications.

The only remaining position for a barrier that need be considered is from the Skaw to the vicinity of Klofero Island. Whatever other barriers may be established farther south, this barrier seems to be an essential protection to vessels supporting the southern barriers against enemy submarines, as well as an additional obstacle to returning submarines. In case of the breakdown of other barriers and of the pushing back of our patrol forces from the Kattegat the Skaw barrier offers a most desirable line to hold.

The closure of the Kattegat would secure for us an area within which traffic might be regulated so as to permit efficient use of submarine-detection apparatus. The Skaw barrier would require the occupation by land forces of the north of the Skaw Peninsula and the occupation of an island position; possibly Klofero, on the Swedish coast. With a given force these positions could probably be held more securely than any of the necessary land positions of the barriers farther south. The number and character of troops and equipment necessary for this work is an Army question. It is sufficient to indicate here that the cooperation of the Army on a large scale will be necessary to any permanency of barrier effort in the Kattegat. Large land forces, however, will entail excessive demands on shipping which, at the present time, will be most difficult to meet. In view of the military and aerial advantages that the


enemy may possess in having Jutland contiguous to his territory, together with good rail communications on the Swedish coast, it is essential that our land positions be susceptible of being held with as small shore forces as possible, and be capable of being well supported by our fleet.

We come now to the consideration of mine barriers protected by naval forces alone—unsupported by the Army. We may assume at the outset that the positions already discussed are as suitable as any others for the barriers. We must recognize that mine barriers, as a submarine obstacle, can only be regarded as effective until such time as the enemy occupies the shores with shore forces and furnished protection, with his artillery, to close-in sweeping operations. We have, however, a decided advantage in that the Kattegat is generally shallow, rendering effective patrol much easier than in deep water. There are no harbors available for patrol craft and supporting vessels except on the Swedish coasts or in Danish waters in the vicinity of Samso Island. These would probably become untenable shortly, so that we should have to look for a base in Norwegian waters. Christiansand, together with adjacent waters, is a suitable place tactically. Its strategic position is excellent except for proximity to probable enemy air bases in Jutland, but this disadvantage is partly compensated for by the dispersion of anchorage ground. The irregular bottom and great number of rocks will render submarine navigation difficult and hazardous.

There is no Norwegian ports farther east equally suitable tactically which will meet strategic requirements. Skudesnaes Fiord is 100 miles farther from the Skaw than is Christiansand. It thus offers greater security against air attack, but corresponding disadvantages for a fleet endeavoring to support operations in the Kattegat. The waters of Skudesnaes are so deep as to render very difficult the berthing of a large fleet. Its defense against submarine attack is more difficult than that of Christiansand.

In view of the measures likely to have been taken by the enemy in anticipation of our projected effort, we must count on strong resistance to our operations and must count further on supporting the operations with the Grand Fleet.


(1) To prepare an expedition establishing a mine barrier at any one of the three southerly positions above discussed, plus the Skaw position.

(2) To provide a gate in the skaw barrier, but no gate in the southern barrier.

(3) To place the southern barrier in the most southerly of the three positions discussed, but to be prepared to accept a more


northerly position if enemy arrangements make the southern barrier an unprofitable undertaking.

(4) To establish an operating base at Christiansand.

(5) To support the whole position with the Grand Fleet.

(6) To arrange, if possible, for the cooperation of the Army.


In presenting the above solution to the Skagerrack problem we submit the following comments on the problem:

(a) Any attempt to block the North Sea ports of Germany against the exit of submarines by means of sinking ships, lighters, and so forth, in its channels, in our opinion is foredoomed to failure.

(b) The Elbe is the most useful of all exits to block, but even there the problem is so difficult that the greatest efforts will have no more than an even chance of temporary success.

(c) The element of surprise is most desirable in dealing either with the Skagerrack or with the Elbe. If circumstances prevent dealing simultaneously with both problems, then the Skagerrack should receive attention first.

(d) The prohibitive features of the military problem in Denmark makes the occupation of an operating base at Christiansand for the Grand Fleet a necessity if the Skagerrack is to be closed.

[Extract from Memorandum No. 71, "History of Planning Section.”]

Subject: "Kattegat Problem."

This was the first strategic problem solved by the Planning Section.

Its solution was undertaken at the request of the Admiralty Deputy Chief of Naval Stuff. We were informed that the British Plans Division had already solved a similar problem, and were requested to refrain from consulting the previous solution.

Consequently, and in view of certain improbable hypotheses made in the problem, we felt that it was in the nature of a test of our abilities and that our solution could be of no direct utility in connection with the war. These beliefs determined us to set our own problems in the future, at least until certain aspects of the war which we deemed of great importance should be examined.


Memorandum No. 7.


14 January, 1918.


Whenever the subject of a reassignment of naval forces comes up, we are obliged to consider first the missions of naval forces in this war and then to determine if the proposed reassignment is in harmony with the adopted mission and with the decisions arrived at for the accomplishment of the mission.

The naval missions deduced from present conditions and from our war aims are, proceeding from the most general to the concrete, as follows:

Basic Mission.—To further a victorious decision on land.

General mission,—To obtain command of the sea.

Special and immediate mission.—To obtain subsurface command of the sea while still retaining command of the surface of the sea.

This latter mission may be stated in a still more concrete form, as follows: To defeat the enemy submarine campaign while still retaining command of the surface of the sea.

We have to consider the advisability of detaching six destroyers from the Queenstown force for service with Division Nine. The first question of all to decide is, Will the proposed assignment assist more in defeating the enemy submarine campaign than the present assignment? It is obviously unnecessary to argue the question; the answer is “No.” The proposed assignment is not an antisubmarine campaign measure. The enemy submarine campaign is primarily against merchant tonnage; it is directed against our armies in the field.

The second question to decide is, Is the proposed assignment of destroyers necessary to retaining command of the surface of the sea? It is over two years since the enemy made any bid for command of the surface of the sea. The present strategic position and condition of the enemy does not require of him that he bring his High Seas Fleet into action. He is accomplishing his ends by a sure, and, to him, satisfactory attack on our communications. The efficiency of this attack would be lessened greatly were his High Seas Fleet to suffer defeat. The fact that his fleet has not risked an engagement for over two years is ample justification for assuming that our con-


trol of the surface of the sea is not in jeopardy. Further, we ourselves know that we have sufficient superiority in numbers and in skill to defeat the High Seas Fleet whenever it throws down the gauge of battle. Knowing this, and knowing further that as yet we are far from successful in our antisubmarine effort, we conclude:

That no destroyers can be diverted to the Grand Fleet from the guarding of merchant tonnage or from any form of antisubmarine effort.


The advantage of a closer association of American destroyers with the tactics of the Grand Fleet, as well as the advantages of an occasional change of duty for the destroyers basing on Queenstown, is recognized.

We therefore recommend that 12 American destroyers of the Queenstown force exchange duty with an equal number of British destroyers from the Grand Fleet, and that after a suitable period a second group of American destroyers relieve the first group, and so on, until all have had service with the Grand Fleet.

We recommend that destroyers arriving on the station from America be assigned first to antisubmarine work.

[Extract from Memorandum No. 71, "History of Planning Section.”]

Subject: “Assignment of Destroyers to the Grand Fleet."

Prepared in response to a recommendation by the commander, Division Nine (American battleships serving with the Grand Fleet), that American destroyers be assigned to duty with the Grand Fleet, in order that valuable experience might be gained.


Memorandum No. 8.


21 January, 1918.



(See Maps Nos. 1, 3, 5, and 6.)

General situation: As at present.

Special situation: The Allies and the United States have decided to continue the war to a victorious peace.

Required: Estimate of the general naval situation in relation to the war as a whole.

Conclusions Reached in the Following Paper.


1. To provide for united action of allied naval efforts, in conformity with the naval missions, and irrespective of local situations and special interests.

2. To unify commands where desirable in certain areas; such as the English Channel and the Adriatic.

3. To reinforce the Grand Fleet with Japanese battle cruisers.

4. To reinforce the Grand Fleet with United States battleships if the barrage operations require it, or if thereby troops in Great Britain can be released for service in France.

5. To develop plans for concentrated air attacks on enemy submarine bases in the North Sea and the Adriatic.

6. To develop plans for attacks with surface vessels against enemy Adriatic bases.

7. To prepare to destroy Russian Baltic ships should their capture by the enemy become imminent.

8. To give special study to the matter of mine barrages in the English Channel and the Adriatic and Aegean Seas.

9. Unless loss of imports is a controlling factor, to immediately occupy a base in Norway, south of the proposed barrage.

Note.—This decision to be abandoned, should it appear probable that the devastation of Norway would result therefrom.


10. To base in Norway a force of battle cruisers, light cruisers, and destroyers superior to any similar force which the enemy is likely to employ in raiding.


1. To devote the maximum possible antisubmarine force to offensive operations.

2. To divert destroyers and other antisubmarine types from Japan, and from other sources, in as great number as practicable to antisubmarine work.

3. To develop with the greatest possible rapidity hunting groups equipped with listening devices, and manned by the best-trained personnel available from all sources.

4. To equip vessels engaged in antisubmarine warfare with adequate means for taking the maximum tactical advantage of every contact with an enemy submarine.

5. To arm heavily (with full gun’s crew for each gun) about 1 merchant ship in 10, of each general class, in the North and South Atlantic; and as far as practicable to escort convoys with such heavily armed merchant ships.

Discussion of Problem.

The following discussion of the problem was set down by the Planning Section, in order to clear up their understanding of the problem and thereby facilitate its solution.

The problem proposed is the most general of all naval problems of the war now in progress.

From the standpoint of joint naval action, the statement of the special situation and of what is required in the solution must be accepted us sound. If we aim at anything less than a victorious peace, we are led to put forth less than our maximum effort, and we commit ourselves to a military policy which can never support properly the aims of belligerents. War has for its object to impose our will upon the will of the enemy. The surest method of achieving this object is by victory, for then the enemy is compelled to submit, and the maximum degree of permanency is given to our achievement.

If we determine upon lines of procedure that are not in proper support of the war as a whole, we thereby favor special interests and introduce friction among Allies that may create dangers of the first magnitude.


The solution of a problem so general as this one is the first step in the formulation of a general plan of action. The first step in the


solution is to determine a statement in concise form of that which the conditions of the problem required should be accomplished. This statement in the first instance takes a sufficiently inclusive form to cover the entire task to be undertaken. A further examination of the task thus determined, in connection with special circumstances, may enable us to determine upon a more concrete statement of the task. When the most thoroughly concrete, and at the same time inclusive, statement of the task is determined, we thereafter investigate the ways of accomplishing the task determined upon, and finally decide upon a definite way for its accomplishment. Thereafter when any related question arises for decision we must examine it in the light of the task to be accomplished, and decide the question in the way best calculated to support the effort to accomplish that task. If the most concrete statement of the task is not sufficiently general to guide us in our decision, we must refer our question to the next general statement of the task, or, as we call it, the mission.

In the problem under consideration, we approach the determination of our naval missions as follows:


The fundamental end in view of sea power is the support of land power. Success on the sea alone can not force peace terms as favorable as those to be gained by corresponding success ashore. The effectiveness of sea power is therefore to be measured by the degree of success with which it fulfills its role as the support of land power.

From these considerations are deduced the basic naval mission in this war—

“To further a successful decision on land.”

The best general means of bringing about sea conditions favorable to shore success lie in the establishment of command of the sea. Such command is useful only in so far as it furthers command of the land, and is not therefore within itself an ultimate objective, but merely one of the preliminary means essential to that end. When it is accomplished, the resources of the friendly and neutral world are made available for the logistical support of our Army and people, and we gain the strategic freedom offered by the sea to strike with, or at, shore power in otherwise inaccessible places, while the enemy is at the same time correspondingly restricted.

The general naval mission is therefore—

“To obtain command of the sea.”

Command of the sea may be established either by destroying enemy naval forces, by effectually containing them, or by so nullifying the effect of their activities as to reduce it to negligible proportions.


At the present time partial command of the sea has been established by the forces of the Allies and the United States. The enemy’s surface craft are effectually contained by an overwhelming force within the immediate vicinity of his home waters—the Adriatic and the Baltic. The enemy fleet commands the Baltic and is free to enter the North Sea, but no movement on its part in those waters can have a serious influence upon our land operations.

The High Seas Fleet is rendered practically impotent by the mere presence of the Grand Fleet covering the exits of the North Sea. On the other hand, the subsurface command of the sea has not been even approximately established. The enemy submarines enter freely the Atlantic and prey upon commerce with the avowed object of impairing the supply and morale of allied civil populace and armies in the field. In other words, submarine warfare is directed against land power, upon which sea power rests, and for the maintenance of which it exists solely.

The enemy is making of submarine warfare his principal naval effort, thus conforming directly with his basic naval mission of “Furthering a successful decision on land.” We are concentrating our major effort on maintaining surface command of the sea, which is doubly assured, while by virtue of his command of the subsea the enemy is placing our land power in serious jeopardy.

Our tonnage losses, with corresponding shortages of fuel, food, and munitions, are already having a great influence on the morale of the civil populations, elevating the enemy’s morale, depressing our own. These losses and shortages are already affecting seriously the main land strategy in Italy and France. They have already made it impossible for the United States to develop quickly its full strength on the western front.

Sinkage of, and damage to, shipping, due to torpedoes, mines, and accidents attributable to the submarine warfare, continue greatly in excess of repairs and new construction, and at a rate which is alarming when viewed from the standpoint of that support to the land power that is essential to prevent defeat.

Our special and immediate mission therefore becomes—

“To obtain subsurface command of the sea, while still retaining command of the surface of the sea.”


Allied Naval Forces. Enemy Naval Forces.

(a) Grand Fleet:
      41 dreadnoughts.
(a) High Sea Fleet:
      19 dreadnoughts.
      5 battle cruisers.


      11 battle cruisers.
      31 light cruisers.
      7 cruisers.
      13 flotilla leaders.
      111 destroyers.
      12 T. S. mine sweepers.
      36 trawlers.
      18 sloops.
      38 submarines.
      5 hydrophone ships.
      3 seaplane carriers.
(b) Harwich force:
      11 light cruisers.
      4 flotilla leaders.
      21 destroyers.
(c) Dover force:
      15 monitors.
      1 light cruiser.
      5 flotilla lenders.
      24 destroyers.
      4 patrol boats.
      2 torpedo boats.
(d) Portsmouth force:
      7 destroyers.
      31 patrol boats.
      4 torpedo boats.
(e) Devonport force:
      40 destroyers.
(f) East coast convoys:
      28 destroyers.
      4 patrol boats.
(g) Queenstown force:
      1 light cruiser.
      37 destroyers (U. S.).
      4 torpedo boats.
      11 sloops.
      9 sweepers.
(h) North coast of Ireland:
      12 sloops.
      27 destroyers.
(i) Firth of Forth:
      10 torpedo boats.
(k) Local defense:
      10 destroyers—Scapa Flow.
      *12 destroyers
      *13 torpedo boats
      #4 destroyers
      #18 torpedo boats
      6 torpedo boats—Portland.
      !3 destroyers
      !7 torpedo boats
      4 torpedo boats—Pembroke.
(l) Submarines:
      68 subs, at various ports.

*The Nore.


      10 light cruisers.
      2 mine-laying cruisers.
      88 destroyers.
      50 torpedo boats.
      30 M. boats.
      45 trawlers.
      (b) Harbor flotillas:
      13 destroyers.
      24 trawlers.
(c) Naval forces in Flanders:
      15 destroyers.
      16 torpedo boats.
(d) Naval forces in Baltic:
      3 light cruisers.
      42 destroyers.
      6 torpedo boats.
      6 M. boats.
      116 trawlers.
(e) Submarine force (including Flanders
      5 light cruisers (old).
      9 destroyers.
      16 torpedo boats.
      6 U. cruisers.
      54 U. type.
      50 U. B. type.
      20 U. C. type.
(f) Training center:
      8 old battleships.
      3 light cruisers.
      12 destroyers.
      3 torpedo boats.
      20 submarines.
(g) Vessels not embodied in regular
      10 old battleships.
      6 coast defense ships.
      3 cruisers.
      13 light cruisers.
      2 mine-laying cruisers.
      33 mining vessels.
      21 destroyers.
      51 torpedo boats.
      50 armed merchant vessels.
      6 auxiliary mine layers.

Summary of British (and U. S.) forces available for fleet engagement :      Summary of North Sea forces: The following summary gives the maximum number of vessels that Germany could bring to bear in a general fleet engagement:  
  Assuming that forces (b), (c), and (f) are available, also local defense destroyers at Scapa Flow, there can be assembled to meet enemy force—    
  19 dreadnoughts.  
  5 battle cruisers.  
  34 light cruisers.  
41 dreadnoughts.     4 mine-laying cruisers.  
11 battle cruisers.     196 destroyers.  
43 light cruisers.     146 torpedo boats.  
7 cruisers.     18 old battleships.  
22 flotilla leaders.     3 old cruisers.  
194 destroyers.     6 auxiliary mine layers.  
Submarines.     150 submarines.  
If the above assumption shall not hold, the Grand Fleet will have—     The torpedo boats are of no value except perhaps in an engagement near the German coast, probably not more than 8 or 10 of the old battleships are in condition for sea.  
  31 light cruisers.    
13 flotilla leaders.    
111 destroyers.    
Probable additions by July 1, 1918:   Probable additions by July 1, 1918:  
  4 dreadnoughts (U. S.).     2 dreadnoughts.  
2 battle cruisers.  
2 light cruisers.  
2 mine-laying cruisers.  
12 destroyers.  
Torpedo boats.  
70 submarines.  
Total forces in British waters apart from Grand Fleet (a) :   Possible addition of Russian Baltic fleet. (It is possible that the following units may be captured or turned over to Germany) :  
  13 light cruisers.    
213 destroyers.    
9 flotilla leaders.     4 dreadnoughts.  
15 monitors.   3 predreadnoughts.  
68 submarines.   9 cruisers.  
64 torpedo boats.   60 destroyers (approx.).  
23 sloops.      
  The above vessels are engaged in escort duty and antisubmarine work. (Does not include trawlers or small patrol boats.)    
French forces in Atlantic:    
  24 destroyers.    
59 torpedo boats.    
25 submarines.    
92 trawlers.    
40 sweepers.    
100 patrol boats.    
10 gunboats.    
  These vessels are distributed in the Channel and Bay of Biscay ports.    


United States naval forces in French Atlantic:  
  30 armed yachts and trawlers.
7 destroyers.
French forces in Mediterranean: Austrian Fleet (Mediterranean):
  7 dreadnoughts.   4 dreadnoughts.
8 predreadnoughts. 6 predreadnoughts.
4 armored cruisers. 4 old predreadnoughts.
6 old cruisers. 2 cruisers.
75 destroyers. 10 light cruisers.
48 torpedo boats. 16 destroyers.
37 submarines. 42 H. S. torpedo boats.
17 gunboats. 2 mine layers.
160 trawlers. 54 submarines (including German).
250 vessels (miscellaneous).
British forces in Mediterranean: Probable additions by July 1, 1918:
  3 predreadnoughts.   2 dreadnoughts.
4 cruisers. 3 light cruisers.
12 light cruisers. A few destroyers and submarines.
14 monitors.
28 sloops. Turkish Fleet:
45 destroyers.   1 old battleship.
18 torpedo boats. 1 battle cruiser.
12 submarines. 2 light cruisers.
Italian forces in Mediterranean: 8 destroyers.
  5 dreadnoughts. 8 torpedo boats.
4 predreadnoughts. ? submarines (German).
5 old predreadnoughts.  
7 cruisers.
10 light cruisers.
7 flotilla leaders.
43 destroyers.
26 R. S. torpedo boats.
50 submarines.
Japanese forces in Mediterranean:
  14 destroyers.
United States forces in Mediterranean (Gib.):
  4 destroyers.
20 other craft.
Summary of Mediterranean forces: Summary of Mediterranean forces:
  12 dreadnoughts.   4 dreadnoughts.
20 predreadnoughts. 11 predreadnoughts.
23 cruisers. 1 battle cruiser.
22 light cruisers. 2 cruisers.
7 flotilla lenders. 12 light cruisers.
181 destroyers. 24 destroyers.
92 torpedo boats. 50 torpedo boats.
100 submarines. 60 submarines.

From an examination of the above disposition of enemy forces, we see that they are divided into three general groups:

(1) The North Sea.

(2) The Adriatic group.

(3) The Sea of Marmora group.


In every case the surface craft are contained and the submarines have exit to the high seas.


The entire subordination of the military and naval strategy of the enemy to his State policies requires that we have in mind his State policies and his present conditions.


(1) Domination of Balkans and Asiatic Turkey.

(2) Extension of colonial possessions.

(3) Commercial supremacy.

(4) Military domination of Europe.

(5) Ultimate naval domination of the sea.

(6) Annexation of provinces rich in mineral resources.

(7) Annexation of ports on the North Sea.


(1) A spreading socialism in Germany and Austria.

(2) War weariness and unrest throughout the Quadruple Alliance. Dangerous conditions in Turkey due to bankruptcy and loss of territory.

(3) A growing apprehension amongst Germany’s allies of conditions which would result from a victorious Germany, unrestrained by a balance of power on the Continent.

(4) Necessity for continued military success to prevent social unrest and to insure continued cohesion of his alliance.

(5) Probable dangerous reaction which would follow a great military reverse, or even partial failure of a great offensive.

(6) Necessity for victory preceding peace, in order to insure continued predominance of present political and military system.

(7) Great opportunity for commercial expansion in Russia beyond any dream Germany might have had at the beginning of the war; modifying her essential requirements with respect to over-seas trade.

(2) [sic] Definite renewal of the postwar Slav threat, permitting a large reduction in the peace standing army and a corresponding increase of naval power.

(9) Antagonism of pan-Germans and nonannexationists.


The only guide to the future policy of the German Army which we can follow is the presumption that the policy it has pursued in the past will be continued. We may assume that Germany plans to hold the western front and to direct her military offensive first against


the remaining weak points of her enemies—the Palestine front, the Salonika front, and the Italian front, unless—

(1) Conditions in Germany are such as to demand an immediate decision on land; or

(2) The Germans believe that their reinforcements on the western front, together with some recently developed surprise weapon, may give them reasonable assurance of victory.

In examining the probable intentions of the enemy, we have first of all to consider the mission imposed upon his naval forces by his situation and aims.

The war that the enemy is waging is a land war. He must succeed on land if he is to dictate the terms of peace. In order to dictate the terms of peace, he must break down the will of his strongest enemies. His strongest enemies are on the western and on the Italian fronts. If he succeeds on both of those fronts, he will win the war. His strategy to date has been to strike on the weaker fronts while holding the stronger fronts. He has endeavored to deprive one front after another of the ability to take the offensive. He has been successful in this on all important fronts, except the western front. He has utilized his successes to strengthen his forces on the more important fronts.

From the beginning of the war he has realized that the great effort of his enemies on the western and on the Italian fronts had to be supported by way of the sea. He has organized the support of his own forces and directed his own land strategy, so that he could do without sea communications outside the Baltic. His basic naval mission has therefore been—

To give the maximum support to his land forces in obtaining a successful decision on land.

The special features of his strategic position have caused him to conclude that he could best support his land forces by naval effort if he concentrated that effort on—

The maximum possible sustained attack on the sea communications of the Allies.

There can be no question that this is the governing mission of his active naval forces to-day, and that it will continue to be their governing mission. Knowing this fact we must not lose sight of its importance nor fail to avail ourselves of the opportunities that the knowledge gives us. The enemy thinks and acts according to his training. He has been taught the doctrine of concentration of effort so long that now it is a part of his nature. He first determines his mission and then devotes all his energy to the accomplishment of that mission. He never loses sight of his mission. Offside effort is no part of his plan, except it promises more toward the accomplish-


ment of his mission than direct effort. He sees his goal and goes toward it with all the power at his disposal.

The enemy has found that his High Seas Fleet can not attack the sea communications of the Allies. He has found that his submarines alone are capable of a sustained attack on the sea communications of the Allies. These facts compel him to assign the principal active role in the accomplishment of his naval mission to his submarines. Such assignment appears to leave his High Seas Fleet without a clearly defined mission. This, however, is not the case. His submarines can not do their work unless they have access to the high seas. His submarines are incapable of maintaining for themselves a freedom of exit to the high seas, but must depend for this upon the High Seas Fleet.

The mission of the High Seas Fleet is therefore, as far as their principal activity is concerned—

To further the submarine campaign to the maximum degree.

This mission includes as an immediate and continuous mission—

To maintain a freedom of passage to and from the high seas for submarines.

Enemy surface craft in the Helgoland Bight, in the Adriatic, the Kattegat, and the Straits of Dover have always striven to keep clear the way for his submarines to the open sea. Their activities have not indicated any other definite intention—any other mission than that given above. We do not refer here to isolated instances of raids and raiders.

The High Seas Fleet serves other and very important purposes for the enemy. Without the High Seas Fleet Germany could not even dream of an invasion of England; with the High Seas Fleet the threat of invasion is sufficient to immobilize a large number of troops in England that might otherwise be on the western front. Further, the High Seas Fleet, by its mere existence in readiness, compels the immobilization of a superior naval force that must be held ready to meet any move the High Seas Fleet may make, which force might, except for the existence of the High Seas Fleet, be used in antisubmarine effort. It would obviously be unsound for the High Seas Fleet to engage in any enterprise that would greatly impair its threat or its holding power, unless that enterprise gave promise of a favorable decision of the war.

The enemy’s strategy on land is closely associated with his strategy on the sea. The enemy attack of the communications of our armies is not for enemy naval forces alone. Enemy armies participate in this attack. The defeat at the Dardanelles was a distinct blow to our communications. It denied to us the war treasures of the Black Sea and equally denied to the Russians a channel of reinforcement. The enemy advance in Belgium to the coast was a distinct attack on


the communications of our armies on the western front. It opened the Belgian ports to his submarines, and gave them the great advantage of proximity to areas congested with our shipping.

We are now in a position to examine the probable intentions of the enemy and then to make use of these in determining upon our courses of action.

In striving to accomplish his missions we may expect the enemy to—

(1) Continue his present submarine campaign.

(2) To enlarge the theater of submarine activity as fast as our antisubmarine measures become effective in congested waters.

(3) To operate his cruiser submarines in distant waters to encourage a dispersal of our forces and to give his cruiser submarines greater tactical freedom. The locality in which a vessel is sunk is no longer of great importance. Quantity of tonnage sunk is what the enemy desires first.

(4) To continue to control the Helgoland Bight, the Kattegat, and the Baltic with his High Seas Fleet.

(5) To concentrate his air activity in support of his land forces, except in so far as aircraft may be required for the protection of naval vessels near their bases.

(6) To intensify his submarine campaign in support of his military offensive—wherever that may be.

(7) There is one possible intention of the enemy that needs careful consideration. We must assume that he knows of the proposed barrage. He must know that we expect to make that barrage effective. He will surely see that we would not make so great an effort without at the same time closing the Straits of Dover. The two efforts, if successful, mean the blocking of his submarines. The mission of his High Seas Fleet is to prevent such a blockade. How will that fleet accomplish that mission? On account of his numerical inferiority in surface vessels, the enemy will foresee the necessity for a base nearer to the barrage than any base that we possess. He will not hesitate to secure the great advantage such a base would give him.

We may expect the enemy to seize a base on the Norwegian coast as soon as we begin laying the barrage, if not before. If such an act is permitted, the barrage will be ineffective until the enemy is driven from his base, or unless we, too, seize a base near him and operate from it with superior forces.

(8) To withhold his High Seas Fleet from operations not directly in support of its mission.

(9) To encourage a dispersion of our air effort and our antisubmarine effort to the detriment of a purely offensive effort on our part.


(10) To handle his High Seas Fleet in such a manner as to immobilize the maximum number of our naval units that might otherwise be used in antisubmarine effort.


Strength and disposition.—As shown above.

Courses open to us.—It is well to repeat the mission of the allied naval forces: “To obtain subsurface command of the sea while still retaining command of the surface of the sea.”

The attainment of the subsurface command of the sea is to-day of paramount importance to the allied forces. Victory or defeat depends upon an immediate solution of this problem. Submarines have sunk 12,000,000 tons of merchant shipping since the beginning of the war, and the sinkings continue at an average rate of 500,000 or 600,000 tons per month. The effect of the shortage of shipping is apparent on the whole allied front from the North Sea to Mesopotamia.


These conditions are necessary for the successful prosecution of war, and are especially so in the antisubmarine campaign, where the maximum effort of all the Allies is essential, and where escort requirements have led to a great dispersal of force.

Greater results can probably be obtained with our air forces and with inshore forces by placing all operations in certain areas, such as the English Channel or the Adriatic, under one command.

The Allies and the United States are handicapped by the lack of central direction to political, military, and naval effort, and by the difficulties of coordination, due to differences of language, race, and political aims, as well as to lack of common doctrines of war.

Individually, we are handicapped by a less perfect system than that employed by the enemy to harmonize military effort, naval effort, and State policy, and to organize and use the entire resource of the State for war. The success or failure of the present military and naval councils will depend on the extent to which they can harmonize and coordinate the allied efforts and bring about unity of action for the purpose of winning the war.


Command of the sea includes two distinct ideas:

(1) The free use of the sea for one’s own forces and commerce.

(2) The denial of such use of the sea to the enemy.


Both of these advantages may be obtained by driving all enemy fighting craft from the sea. During the period when the command of the sea is not complete, we require two forces of military effort:

(1) Offensive effort directed against all enemy vessels, and, where possible, against their bases.

(2) Defensive effort, which in general gives local protection to vessels at sea.

The Allies have retained surface command of the sea since the beginning of the war. Isolated raiders have escaped from the North Sea, and attacks have been made on the English coast and Norwegian and Dutch convoys; but such enemy action can not be entirely prevented, and has but a small influence on the course of the war.

The Grand Fleet has a superiority of nearly 2 to 1 over the High Seas Fleet in all units except destroyers.

The mission of the High Seas Fleet is—

“To further the submarine campaign to the maximum degree.”

We are reasonably certain that the High Seas Fleet will never seek decisive action, nor place itself in serious jeopardy, unless it is necessary to secure the free passage of submarines to the open sea.

The following present and future features of the North Sea situation may render an increase of the Grand Fleet necessary:

(1) The possible addition of the Russian Navy to enemy forces— 4 dreadnoughts and about 60 destroyers.

(2) The added sense of security that the Grand Fleet reinforcements will give to Great Britain against any fear of invasion.

(3) Future developments in connection with the North Sea barrage which may require considerable detachments from the Grand Fleet.

(4) The escape to the Atlantic of enemy battle cruisers as commerce destroyers.

The addition of Russian battleships to enemy forces can be met by the transfer of United States battleships to European waters. The Russian destroyers may be met by new construction, the transfer of destroyers from antisubmarine operations, or the addition of Japanese destroyers.

Our submarines in the Baltic may destroy Russian ships when danger of the enemy taking them over becomes imminent. It is important that the enemy be prevented from getting many Russian destroyers, if possible.

In detachments for the protection of the North Sea barrage, or for running down enemy battle cruisers in the Atlantic, battle cruisers are of great value. The only available additional units of this class are the four J battle cruisers, and their addition to the Grand Fleet is most desirable.


If the transfer of United States battleships to the Grand Fleet will allay in Great Britain the fear of invasion to such an extent that a considerable number of troops will be released for service in France, then such a transfer is justified. The aim always is greater strength on the fighting fronts. It is immaterial how that strength is obtained.

In the Adriatic, surface command is held in great force by the Allies over the Austrian and Turkish fleets. Even the withdrawal of Italy would still leave a sufficient excess of force.

Owing to future probable difficulties of maintenance of capital ships in the Mediterranean, the destruction of the Austrian Fleet is of importance. Of greater importance is the destruction of enemy submarine bases, which may be undertaken by our surface and air forces.


The destruction of the submarine bases would be an effective method of solving the submarine problem.

The enemy North Sea bases may, however, be considered as impregnable. Apart from fortifications, the physical features of the coast with the extensive banks and reefs, lowland, and narrow and tortuous channels, leading up to the principal naval bases, render a combined naval and military expedition against them a desperate undertaking with practically no chance of success.

The destruction of these bases depends upon the future development of air craft. Present machines have insufficient radius to attack Wilhelmshaven or Kiel.

Zeebrugge, however, is within easy air distance of England or France. Numerous raids have been made on this place, but owing to the provisions made to protect submarines from air attack, and to the advantage offered by the Bruges Canal to disperse and hide submarines, it is probable that the results have been small.

Zeebrugge appears to be of sufficient importance to warrant the concentration of adequate air power to maintain a permanent air superiority and to continue bombing it until it becomes untenable as a submarine base. Such an effort will also undoubtedly have a direct result on the military campaign in France.

The Adriatic bases are all within easy air distance of the Italian coast, and an intensive attack on all these bases should be considered. The additional destruction of the Austrian surface fleet would have a valuable effect in releasing colliers and supply vessels required for the allied containing force.

Such a campaign on a large scale against submarine bases in both the North Sea and Adriatic will involve withdrawal of many airplanes from present patrol work, and will require a reconsideration


of the present plans of widely distributing air stations along the coasts.

During the month of December, British aircraft covered 140,000 miles in antisubmarine work; 23 submarines were sighted, 20 attacked, and none was sunk. The effort seems out of proportion to the results achieved. Beyond any doubt, a concentration of this effort on a known base, ease of access, would have yielded greater results.

Concentrated offensive air power in Flanders and southeast England will not only accomplish greater results against submarines, but it will also relieve the air threat against London, definitely give us command of the air at a great strategic point, and directly assist the armies in the field—the ultimate object of all our naval and air effort.


This has been tried, both off Zeebrugge and off Helgoland during the war. While it may have resulted in the losses of some submarines, the general result has been a failure, as the enemy soon clears a passage. In such future operations it may be assumed that to be effective the barrage must be patrolled. The laying of mine barrages in the Adriatic and Aegean Seas should receive consideration.


At present there is under way the placing of the Dover and North Sea barrage in an effort to contain submarines in the North Sea.

As this effort is on as great a scale, certain features which involve its success or failure should be discussed in full.

We have recently had an example of a barrage patrol in the Straits of Otranto. The supporting bases were near. The weather conditions better than in the North Sea. Capital ships in comparatively great strength were in the near vicinity, and yet it was not practicable to maintain a patrol barrage. The attacking force could attack and get away without serious danger of being cut off because it occupied an interior position. Information of its movements always came too late to permit any action by allied forces that were not at sea on the line of retreat. The patrol had to be abandoned.

We may expect similar action and similar results in the North Sea unless we station our supporting forces in advance of the barrage. Manifestly it is impracticable to hold supporting forces of large vessels continuously at sea in advance of the barrage. The Scotland-Norway patrol was abandoned because of submarine activity. The problem then is to find a way of holding strong forces


in readiness between the enemy naval bases and the barrage. We see no way of doing this except by occupying a harbor on the Norwegian coast. Fanciful schemes of mined-in areas at sea might be discussed, but the conclusion would still be the same.

A harbor south of the barrage on the Norwegian cost is the only satisfactory solution to the support of the barrage as a whole.

In considering harbors that may be available we should give preference to those harbors having the greatest capacity that are capable of secure temporary defense. As the war progresses and the passive features of the barrage become more effective, we must expect increased effort to break the barrage so that the attacking defense of the barrage may become a matter of fleets. We shall be in a strong position if we can, at will, base the Grand Fleet on the Norwegian coast.

There is an advantage in selecting a base some distance south of the barrage for the following reasons:

(1) Increased probability that a movement toward the barrage will be detected in time to give warning.

(2) Increased opportunity to intercept any force that raids the barrage patrol.

(3) Denial to the enemy of all positions north of the base selected.

Assuming for the moment that a base can be acquired on the

Norwegian coast, the question arises as to what force should normally be based there.

The mission of the force will be—

“To intercept and destroy any enemy force of surface vessels that may approach the barrage.”

Enemy forces that have operated so far from base as the barrage are of three classes—submarines, merchant-ship raiders, and light cruisers. If greater strength is needed in the raiding force, the next step would be to send battle cruisers.

Whatever is sent on these expeditions will have high speed. The mission of the expedition will be the destruction of patrol craft, since these are the vessels that block the way of the submarine. Having destroyed the patrol craft, the next mission of the expedition will be to get home. If it is pursued by slow vessels—battleships, for instance—it will experience no difficulty in getting home. We are, therefore, compelled to assign powerful high-speed vessels to operate from the proposed base. The number of these vessels should exceed the number of similar vessels likely to be sent against the barrage. They should be reinforced by an information service of light cruisers, and of listening vessels capable of giving timely warning.

It is, of course, desirable that the base for patrol craft should be near the area they patrol. If we are to acquire any base at all in Nor-


wegian waters, the acquisition of an additional base will not unduly complicate the political situation.

We have now arrived at the following conclusions:

(1) A base on the Norwegian coast is essential to the maintenance of an effective barrage.

(2) The base for supporting vessels should be between the barrage and the enemy bases.

(3) The supporting vessels should be battle cruisers. Battleships may be used in addition, but would be of small use unsupported by battle cruisers.

(4) The supporting force should include an information service of light cruisers and listening vessels.

The question then at issue regarding the maintenance of effective barrage is, Shall a Norwegian base be acquired?

Answer: If Norway consents, and without danger of war with Sweden or Germany—Yes, immediately.

Note.—The possibility of war between Norway and Sweden, or between Norway and Germany, as a result of the occupation of a base by us must be considered. If we knew that such a war would occur as a result of the occupation, we would decide against the act, because the strategic value of the base and of the barrage does not, in our opinion, warrant the devastation of Norway. Attention is invited to a previous memorandum concerning the characteristics essential to an efficient mine barrage.


This has greatly reduced the loss from enemy action, and must be adhered to until losses have been considerably reduced from the present rate. Convoy has serious disadvantages, however, among which are:

Reduction of efficiency of shipping (estimated to be about 50 per cent).

Losses by collision.

The loss of efficiency can be decreased by—

Better utilization of speed.

Convoys to make the best possible speed from port to port.

Thorough instruction of merchant officers in rules for convoy.

Placing all merchant vessels and personnel of the allied countries under Government control.


When operations inshore become too dangerous, the enemy submarines will naturally move further offshore. Forcing them to this will be a decided gain, as shipping will be harder to find and the


maintenance of submarines on station more difficult. On the other hand, the greater number of patrol vessels are unsuited for deep-sea work, and the greater immunity of submarines will partially counterbalance the difficulty in finding shipping, and the disadvantage of the necessarily reduced number of submarines on station.

It is probable that the development of antisubmarine methods on the European coast will result in an attack in force on shipping along the United States Atlantic coast, Gulf of Mexico, and Caribbean. Submarine fuel carriers will permit of submarines remaining for a considerable period in the western Atlantic.


As has been stated, this is the greatest and most vital problem that confronts the Allies to-day. It must be solved and solved quickly. The outcome of the war depends upon it. In its achievement, the line of action will be guided by the following principles:

1. The offensive should be followed in every possible case.

2. Greater results are promised by action close to enemy bases.

3. A pure defensive leading to the dispersal of units over great areas has practically no hope of success. The effort involved is prohibitive, as compared with that of the enemy.

4. Every contact with a submarine should be followed by the maximum tactical offensive effort for its destruction.

The present surface command of the sea is largely a passive effort governed by the idea of an offensive whenever the opportunity presents itself. Subsurface command can be obtained only through offensive effort. All other effort is palliative. The conclusive effort must be offensive, even in its palliative measures. The offensive idea in antisubmarine warfare is of specially great importance. The submarine navigates in three dimensions. Every time it is forced to submerge it enters a danger zone disturbing to morale. Every time it is forced to submerge off soundings it enters a zone of special danger where any outward event may mean disaster. When we limit our antisubmarine measures to escort duties, we do the thing most calculated to favor the morale of the submarine personnel. The crews lead a comparatively placid life except when they are about to attack; then all hands are called and they go about their duties deliberately according to plan. If, however, we can convert this feeling of comparative security to one of constant tension, the effect will show immediately in increased submarine losses. Greater strain, more frequent emergencies, and the consequent general feeling of insecurity incident to being the chased instead of the chaser can not but have a marked effect.


We therefore adopt as a principle that “The maximum possible antisubmarine force shall be devoted to offensive operations.” Offensive operations against submarines finally culminate in tactical situations where one or more submarines are pitted against one or more submarines or surface vessels. The entire submarine problem as it exists to-day is nothing but the assemblage of a multitude of tactical situations of the above nature. The successful solution of two or three typical situations would mean the ultimate solution of the entire problem. The ultimate solution to the submarine menace is tactical and not strategic.

We understand that the enemy entrusts his submarine to skilled officers specially trained to perform their specific duties. If we are to defeat an effort in which initiative clearly lies with the enemy, we must oppose skill with greater skill; we must make of our antisubmarine effort a major effort that claims the best brains and the best tactical skill of the naval services. We must assure ourselves that on every occasion of contact with a submarine the maximum tactical use shall be made of that contact. To realize this aim we must prepare both vessels and personnel for their mission.

As to personnel, the solution is to be found in the best available personnel thoroughly trained in the best known methods. We feel that every branch of the United States and allied naval services is fully justified in giving large numbers of its best people to the antisubmarine service. The recent rapid development of submarine-detection devices is of such a nature as greatly to modify the tactics of submarine search and attack. It is therefore necessary to train personnel in the new tactics as fast as possible. It is suggested that conferences at the Admiralty of the best qualified officers actually operating at sea in antisubmarine work would be useful in determining, improving, and disseminating tactical methods.

As to vessels and their equipment, they must be ready to deliver the maximum possible attack. We may assume readiness as to the gun attack. The depth-charge attack is still in an unsatisfactory condition, but rapidly being improved.

In reports from American destroyers there have been several instances of depth charges failing when, if they had not failed, the submarine would have been put down. Such instances indicate the desirability of adopting the rule of always dropping at least two depth charges simultaneously. Experience has demonstrated that the position of a submerged submarine is known with more accuracy immediately upon the arrival of the attacking vessel near the point of submergence than it is at any later time. This fact indicates the desirability of making the first depth-charge attack a maximum effort. Vessels should therefore be provided


with means for projecting depth charges from the stern and from the beams so that a large area of water—say two or three hundred yards in diameter—may be covered by the simultaneous discharge and dropping of depth charges. Dropping gear for two depth charges with projectors for two depth charges located near the stern and three or four on each beam or quarter is suggested. In addition as many depth charges as can be carried aft should be in readiness for running over the stern (mine-laying style) so that they may be laid on retiring curves. It should be a principle of action that—

The first contact with an enemy submarine shall justify the expenditure of all depth charges on board but two.

The after gun and torpedo tubes of destroyers used in antisubmarine work can be landed to make way for more depth charges and the gear necessary for using them expeditiously.

To summarize our antisubmarine effort:

(1) Emphasize the offensive as much as possible.

(2) Put the best brains and skill available into the antisubmarine service.

(3) Develop group tactics and organization by conference and otherwise. Disseminate results.

(4) Make maximum possible use of each contact with a submarine.

(5) Always drop at least two depth charges in first salvo, and as many more as possible. Expend all but two depth charges on first contact with a submarine.

(6) Fit vessels to carry maximum possible number of depth charges in readiness for laying expeditiously. Remove after gun and torpedo tubes on destroyers if necessary.

The question of the cruiser submarine is one very difficult of solution, because of its extensive field of operations. Tactically it is less efficient than the small submarine, except for the increased range of its guns. The tendency of our answer to the cruiser-submarine attack will be toward a further diversion of forces to defensive arrangements and a further slowing up of shipping through extension of the convoy system. Even were it sound policy it is impossible to guard shipping in distant waters against the torpedo attack of cruiser submarines. Greater zigzag areas, increased armament of merchant ships, increased numbers and skill of armed guards, increased vigilance regarding lights, smoke, etc., all palliative measures, is the best reply available at present to the cruiser submarines. In connection with the increased armament of merchant vessels as a reply to the gunfire of the cruiser submarine, we suggest the special arming of about 1 merchant ship in 10 of each class with


a battery of at least four 5-inch or better guns, and the assignment to those ships of a full gun’s crew for each gun. As the convoy system becomes more fully organized, it will then be possible to place one specially armed ship in each convoy, and thus be sure that in the absence of an ocean escort we will still have sufficient gun power with each convoy to reply to the gunfire of a cruiser submarine.

The Mediterranean situation is entirely satisfactory as to the containing of enemy capital ships, but the submarine situation is very unsatisfactory. Submarines cruise at will and safely throughout the Adriatic and Mediterranean, basing chiefly on Adriatic ports. The principal obstacle to patrol operations in the Adriatic has been the activity of enemy light cruisers and destroyers. We recommend no withdrawal of forces from the Mediterranean, but that closer study of the Adriatic situation be made with a view of a greater concentration of offensive effort against enemy naval forces. We consider the entire naval problem of the Mediterranean and Adriatic a major problem in which the United States and the Allies are all greatly interested.

The successful solutions of this problem might well mark the turning point in the war.



1. To provide for united action of allied naval efforts, in conformity with the naval missions and irrespective of local situations and special interests.

2. To unify commands where desirable in certain areas, such as the English Channel and the Adriatic.

3. To reinforce the Grand Fleet with Japanese battle cruisers.

4. To reinforce the Grand Fleet with United States battleships if the barrage operations require it, or if thereby troops in Great Britain can be released for service in France.

5. To develop plans for concentrated air attacks on enemy submarine bases in the North Sea and the Adriatic.

6. To develop plans for attacks with surface vessels against enemy Adriatic bases.

7. To prepare to destroy Russian Baltic ships should their capture by the enemy become imminent.

8. To give special study to the matter of mine barrages in the English Channel and the Adriatic and Aegean Seas.

9. Unless loss of imports is a controlling factor, to immediately occupy a base in Norway, south of the proposed barrage.

Note.—This decision to be abandoned should it appear probable that the devastation of Norway would result therefrom.


10. To base in Norway a force of battle cruisers, light cruisers, and destroyers superior to any similar force which the enemy is likely to employ in raiding.


1. To devote the maximum possible antisubmarine force to offensive operations.

2. To divert destroyers and other antisubmarine types from Japan and from other sources in as great numbers as practicable to antisubmarine work.

3. To develop with the greatest possible rapidity hunting groups, equipped with listening devices and manned by the best-trained personnel available from all sources.

4. To equip vessels engaged in antisubmarine warfare with adequate means for taking the maximum tactical advantage of every contact with an enemy submarine.

5. To arm heavily (with full gun’s crew for each gun) about one merchant ship in ten, of each general class, in the North and South Atlantic, and, as far as practicable, to escort convoys with such heavily armed merchant ships.

[Extract from Memorandum No. 71, “History of Planning Section."]

Subject: “Estimate of the General Naval Situation in Relation to the War as a Whole."

This was the first strategic problem set itself by the Planning Section. It was selected partly with a view to self-education, but also with a desire to contribute something useful toward the prosecution of the war.

Following favorable comment from the Force Commander and the Admiralty, it was thought that the solution might prove of greater value if it received wider circulation and If the conclusions reached should be approved in principle by the Inter-Allied Council.

It was accordingly submitted as a part of the agenda for the Inter-Allied Council and subsequently received the approval of that body. It was the subject of favorable informal comment by French and Italian officers.

The influence which the paper exerted upon the conduct of the war is difficult to estimate. Some of the conclusions reached were already in process of design or execution by the Allies; others were rendered impracticable by subsequently changed conditions. Nevertheless it was apparently the first comprehensive examination of the naval aspects of the war made by any of the allied staffs, and as such it served to clarify thought and to unify conceptions and effort among the Allies.

Forwarding comment by the Force Commander on 31 May follows:

“1. Inclosed herewith arc corrected pages 17 and 18 for Planning Section Memorandum No. 8, a copy of which was forwarded to the Department on February 22.

“2. The changes front the pages 17 and 18 previously forwarded are such as to eliminate from the memorandum all references to the seizure of a base in Norway.

“ 3. All copies of this memorandum which were furnished to the Allied Naval Council and to the British Admiralty were altered in accordance with the inclosed corrected sheets.”


Memorandum No. 9.


30 January, 1918.

(See Maps Nos. 6 and 7.)



In judging the soundness of the conclusions arrived at in the following paper, which may be found upon the last pages, it is urged that the following points receive consideration:

(1) The value of an offensive attitude whenever such offensive attitude is possible.

(2) The soundness of the principle of concentration of effort.

(3) The great importance of unity of command, and, in the case of allied operations, the extreme importance of deciding beforehand upon spheres of activity.

(4) The principle of attacking the enemy where he is weakest. Enemy morale in Austria and in Turkey is weaker than in Germany. The attack upon the morale in either of these countries is a flank attack upon German morale; this we can not afford to neglect.

(5) The weakened morale of Italy, due to recent reverses, requires of the Allies that an extraordinary effort be made to build that morale up again to its former high standard.

(6) That success in the Adriatic would release large forces for other important operations and make possible a still greater concentration of effort in the areas which finally must be the areas of critical importance.


General situation: As at present. Enemy submarine activity in the Mediterranean causes serious losses to allied and neutral shipping. Practically all submarines operating in the Mediterranean base on ports in the Adriatic and pass through the Straits of Otranto.

Special situation: The Allies and the United States decide to prevent the use of ports in the Adriatic as bases for enemy submarines operating in the Mediterranean.

Required: Estimate of the situation and plans for—

(a) Decreasing immediately losses due to submarine activity in the Mediterranean.


(b) Denying the use of Adriatic ports as bases to enemy submarines.

(c) Organization of allied command. Scheme for cooperation of forces.


On January 21, 1918. the Planning Division submitted a solution of the following problem:

Problem No. 2.

General situation: As at present.

Special situation: The Allies and the United States have decided to continue the war to a victorious peace.

Required: Estimate of the general naval situation in relation to the war as a whole.

In solving the above-quoted general problem the Planning Section determined, first of all, that the basic naval mission in this war is—

“To further a successful decision on land.”

From this basic mission the general naval mission was derived, as follows:

“To obtain command of the sea.”

Since the command of the surface of the sea had already been obtained, the special and immediate mission was determined to be—

“To obtain subsurface command of the sea while still retaining command of the surface of the sea.”

In the general and detailed investigation as to methods of obtaining subsurface command of the sea, while still retaining command of the surface of the sea, the following conclusions were arrived at:

Conclusions Reached in the Previous Paper.


1. To provide for united action of allied naval efforts, in conformity with the naval missions and irrespective of local situations and special interests.

2. To unify commands where desirable in certain areas, such as the English Channel and the Adriatic.

3. To reinforce the Grand Fleet with Japanese battle cruisers.

4. To reinforce the Grand Fleet with United States battleships if the barrage operations require it, or if thereby troops in Great Britain can be released for service in France.

5. To develop plans for concentrated air attacks on enemy submarine bases in the North Sea and the Adriatic.

6. To develop plans for attacks with surface vessels against enemy Adriatic bases.

7. To prepare to destroy Russian Baltic ships should their capture by the enemy become imminent.


8. To give special study to the matter of mine barrages in the English Channel and the Adriatic and Aegean Seas.

9. Unless loss of imports is a controlling factor, to immediately occupy a base in Norway, south of the proposed barrage.

Note.—this decision to be abandoned should it appear probable that the devastation of Norway would result therefrom.

10. To base in Norway a force of battle cruisers, light cruisers, and destroyers superior to any similar force which the enemy is likely to employ in raiding.


1. To devote the maximum possible antisubmarine force to offensive operations.

2. To divert destroyers and other antisubmarine types from Japan, and from other sources, in as great number as practicable to antisubmarine work.

3. To develop with the greatest possible rapidity hunting groups, equipped with listening devices and manned by the best trained personnel available from all sources.

4. To equip vessels engaged in antisubmarine warfare with adequate means for taking the maximum tactical advantage of every contact with an enemy submarine.

5. To arm heavily (with full gun crew for each gun) about 1 merchant ship in 10, of each general class, in the North and South Atlantic; and as far as practicable to escort convoys with such heavily armed merchant ships.

Of the above general conclusions in the solution of the general problem, the following conclusions bear directly upon the problem now under consideration: 1, 2, 5, 6, and 8; and of the conclusions regarding antisubmarine warfare, the following hear upon the problem now under consideration: 1, 3, and 4.

Estimate of the Situation.

Mission: To prevent the use of ports in the Adriatic as bases for enemy submarines operating in the Mediterranean.


Strength, and disposition naval forces (January 1, 1918).

First squadron based on Pola: Additional vessels based on Pola:  
4 dreadnoughts (Uiribus Unitis — 12-12" guns). 1 battleship, second class (Mars).  
3 predreadnoughts (Radetzky — 4-12" guns; 8-9.4" guns). 2 light cruisers (old — 19 knots).  
3 torpedo vessels (old — 14-20 knots).  
3 predreadnoughts (Erzherzog— 4-9.4” guns; 12-7.5" guns). 2 mine layers.  
18 auxiliaries (mine vessels, tenders, yachts, colliers, etc.)  
3 predreadnoughts (Habsberg— 3-9.4"; 12-5.9").  
Cruiser flotilla based on Cattaro:  
2 predreadnoughts (Monarch — 4-9.4"; 12-5.9"). 2 cruisers (Sankt George—21 knots; 2-9.4"; 5-7.5").  


Cruiser flotilla based on Cattaro—Con. There are also the following:
  6 light cruisers (4 of 27 knots; 2 of 20 knots).   8 armed auxiliaries (4 at Trieste).  
16 destroyers (400-800 tons; 28-33 knots). Summary of enemy forces—Adriatic:  
  4 dreadnoughts.  
42 H. S. torpedo boats (200-250 tons; 25-21) knots). 11 predreadnoughts.  
2 cruisers.  
Additional vessels based on Cattaro: 4 light cruisers (27 knots).  
  1 battleship, second class (old). 6 light cruisers (20 knots).  
2 light cruisers (old—19 knots). 22 destroyers.  
2 auxiliary cruisers.  
51 H. S. torpedo boats.  
1 torpedo vessel.  
18 torpedo boats, first class.  
1 mine depot vessel.  
28 torpedo boats, second class.  
2 submarine depot ships.  
54 submarines (Austrian and German).  
1 mining tender.  
1 repair ship.  
13 Austrian submarines. 10 torpedo vessels (old).  
12 U. submarines (German). 8 mining vessels.  
12 U. B. submarines (German). 8 armed auxiliaries.  
15 U. C. submarines (German). Vessels building—Adriatic:  
Also some torpedo vessels and H. S. torpedo boats.   4 dreadnoughts (2 laid down in 1914).  
Based on Lussin: A few torpedo boats. 3 light cruisers (1 laid down in 1914).  
Based on Sebenico:  
  2 repair ships. 4 destroyers.  
1 gunboat. 13 torpedo boats.  
4 coastal torpedo boats. 8 submarines.  
1 sloop. Turkish forces—In general based on
  3 auxiliaries.  
Vessels where station is not known:  
  5 torpedo vessels.   1 predreadnought.  
  6 destroyers (probably at Cattaro). 1 battle cruiser — Goeben. (Probably damaged so as to be
unserviceable for some time.)
  9 H. S. torpedo boats.  
  18 torpedo boats first class (some at Lussin). 1 light cruiser.  
8 destroyers.  
  28 torpedo boats second class (6 used as mine sweepers). 7 torpedo boats.  
3 Turkish submarines.  
  2 submarines. 4 or 5 German U. B’s. and U. C’s.


In the following summary of military strength, only those forces which have to do directly with the defense of enemy bases are considered.

Trieste.—Fortified; several batteries, including 14 heavy guns, caliber not known. Shipbuilding plants and fuel depots; probably all oil fuel for submarines comes into Trieste and is sent to Pola and Fiume by rail, and by water to Cattaro. Approaches to Trieste are comparatively shallow, so that submarine operations against any surface craft in that vicinity would be correspondingly difficult. Position of Trieste, 60 miles from Venice, makes it within easy reach of air attack.


Pola.—Heavily fortified. Important naval base. Considerable repair facilities. Twenty fathoms of water off the port. Seventy miles from port Ravenna or Rimini. Bombardment by fleet not promising.

Fiume.—Fortification unknown. Important repair facilities. Approaches difficult and fortified. Ninety miles from Venice.

Lussin Piccolo.—Torpedo-boat station. Unimportant; well fortified. Garrison in 1915 reported to be 1,500.

Zara.—Torpedo-boat station. Unimportant; no permanent modern defenses.

Sebenico.—Destroyer base and seaplane station. Coal depot— 120,000 tons in 1915. Fortified. Considered impracticable by Austrian officers to attack from sea.

Scardona.—Coal mines close at hand; coal of poor quality.

Spallato.—Torpedo-boat station. Has considerable military importance. Has no railway communication with rest of Empire. Submarine base at Trau. Oil-fuel store there.

Gravosa.—Naval coaling station. Probably a torpedo-boat station. When Austrian fleet anchors off this port it enters Ombla Inlet.

Cattaro.—Naval base, with stores and workshops. Strongly fortified by 14 modern forts and batteries mounting guns up to 12-inch. The defenses are reported to have been added to since the war began. Montenegrin heights to the east of Cattaro completely dominate it and render its capture by land difficult. Permanent defenses include the following guns:

Twenty-five 21-centimeter mortars.

Sixteen 15-centimeter guns.

Twelve 9-centimeter guns.

Twelve 7-centimeter guns.

Numerous field guns.

Cattaro is connected to bases farther north by a narrow-gauge railroad, 30-inch, which has many very steep grades necessitating rack and pinion at several points. The road has tunnels both in the coast section and in the interior section. The road lies along the coast for a distance of 20 miles north of Cattaro, and then for 30 miles farther runs within 10 miles of the coast before it turns inland. The capacity of the road to support forces based on Cattaro does not exceed 10,000 men. A broad-gauge road is under consideration from Cattaro to Mostar, a town on the narrow-gauge railroad about 120 miles from Cattaro.

In addition, defensive works have been established at Duino, Salvore Point, Robigno, Lovrano, Bucari Bay, Zengg, Carlopago, Brazza Island, Narento River, and Ragusa.

Submarine bases have been established at Port Rose, Istria, Port Salbore, Lagosta, Meleda, Trau, Umago, Primero, and Cattaro.


The enemy has an extensive coastal signal system, including stations at Lagosta and Pelagosa Island (south of Curzola Island).

The enemy has strong military forces against Fiume and along the Semini River, just north of Valona. In the intervening coast districts, however, he has but relatively weak land forces distributed about as follow numbers are approximate only):

Sebonica, 8,000 (Bosnian Landsturm).

Spallato, 2,000.

Gravosa, 2,000 (Landwehr).

The country lying between the enemy’s principal forces in the North and the South Adriatic is very rugged and mountainous, with but few good roads, and these principally near the coast

Wireless station of the enemy are located at—

Cattaro — medium power.

Lissa Island — low power.

Lussin Piccolo — low power.

Sebonico — medium power.

Pola — high power.

Trieste — high power.

Guippana Island — low power.

Fuel.—The principal sources of coal supply are the Dalmatian mines, which furnish coal of an inferior quality. Fuel oil for submarines probably comes by rail from the Galician and Roumanian oil fields to the northern bases.


Any survey of the enemy strength on the Adriatic would be incomplete without pointing out the value of his strategic position in the Adriatic in its relation to our lines of supply and operation in the Mediterranean. The Adriatic positions, and specially Cattaro, lie close on the flank of all communications between Gibraltar and Saloniki and between Gibraltar and Egypt. They also threaten with almost equal facility all lines of communication leading from Gibraltar to Italian and French Mediterranean ports.

In addition to the value of these positions and their relations to the Mediterranean, the enemy derives further strength from the nature of the eastern coast line of the Adriatic from Cattaro to Trieste. In this region water communication for the enemy is favored by numerous inland passages sheltered by islands and by the high land of the mainland.


In examining the probable intentions of the enemy in the Adriatic region we have first of all to consider the mission imposed upon his naval forces by his situation and aims. The Adriatic situation is one


of the factors in the great problem of the present war, and a most important factor.

The war that the enemy is waging is a land war. He must succeed on land if he is to dictate terms of peace. From the beginning of the war he has realized that the mission of his naval forces was to support his land forces in order that the position on land might be in his favor. This idea might be expressed more concretely by saying that the enemy’s basic naval mission is—

“To give the maximum support to his land forces in obtaining a successful decision on land.”

The special features of his strategic position from the naval point of view have caused him to conclude that he can best support his land forces by naval effort, if he concentrates that effort on—

“The maximum possible sustained attack on the sea communications of the Allies.”

There can be no question that this is the governing mission of his active naval forces to-day, and that it will continue to be the governing mission.

The enemy has found that his surface vessels could not attack the sea communications of the Allies without such danger as to render their annihilation practically certain. He has found that his submarines alone are capable of a sustained attack on the sea communications of the Allies. These facts compel him to assign the principal active role in the accomplishment of his naval mission to his submarines. His submarines can not do their work unless they have access to the high seas. They are incapable of maintaining for themselves a freedom of exit to the high seas, but must depend for this upon the activities of surface vessels. The mission of the enemy surface vessels in the Adriatic therefore becomes—

“To further the submarine campaign to the maximum degree.”

This mission includes an immediate and continuous mission—

“To maintain freedom of passage to and from the Adriatic to the Mediterranean for submarines.”

The presence of the enemy surface vessels in the Adriatic serves to immobilize a superior naval force of the Allies, in order that the Allies may guard surely against raiding activities of enemy surface vessels.

Enemy operations in the Adriatic so far, both of his surface vessels and his submarines, have resulted in making the Adriatic practically an Austrian lake in which no allied naval operations of importance are undertaken. This status of the Adriatic facilitates greatly the use of Cattaro as a base, and thereby adds to the efficiency of the submarines operating in the Mediterranean by reducing the distance from their bases to their field of operations.


When we examine the probable intentions of the enemy we have to consider them first on the presumption that present conditions in the Adriatic continue without marked change. Under these conditions it is safe to assume that the enemy will—

(a) Hold his capital ships in reserve in northern Adriatic bases as at present, and will not offer action with them unless such action is necessary to keep open the Adriatic for the exit of his submarines.

(b) Base his submarine operation on Cattaro and operate from there to the maximum of his ability.

(c) Base enough light cruisers, destroyers, and so forth, on Cattaro, to make it difficult to maintain a surface patrol or barrage in the Straits of Otranto, and to continue to operate these craft as heretofore offensively against exposed forces of the Allies.

(d) Continue to raid Italian coast towns for the moral effect of such raids.

In case allied operations in the Adriatic are such as to separate Cattaro definitely from northern bases, and to establish a barrage between northern bases and the Mediterranean, we may expect that the enemy will—

(a) Shift the base of his submarine operations to Constantinople.

(b) Attempt to break the barrage in the Adriatic and drive the allied forces back as far as their present position.

(c) In case it is impracticable to shift his submarine base to Constantinople, the enemy may attempt by land operations in Grecian territory to gain new positions for submarine bases.

(d) The enemy will not, under any avoidable conditions, accept a principal base of submarine operations inside of an effective allied barrage.

(e) If Cattaro should be separated from the northern bases simply by the interposition of an allied base, the enemy would not withdraw his submarines to northern bases until local conditions of supplies and fuel at Cattaro compelled such a withdrawal.

The points already mentioned bear upon the general situation of the enemy, and upon measures which may be taken to further successful war against him.

At present the enemy is assisted in his naval operations in the Adriatic by his ability to escape to a conveniently located base after each raid on surface vessels in the Otranto region.

The enemy is assisted in all his operations by his present occupation of islands in the eastern Adriatic.

The enemy is hampered somewhat in the operations of his surface craft by poor coal and a possible insufficiency of fuel oil.

The inhabitants of the islands in the eastern Adriatic are not staunch supporters of the enemy.

The communications, both by land and sea, of Cattaro are poor.


The enemy morale is good, but not so good as that of the Germans, nor need we expect any particular efficiency in the operations of his surface vessels if opposed to vessels of equal strength.

An active naval offensive, if only partially successful, would have a very depressing effect on his morale, as present reports indicate decided unrest and hardship in Austria.

The great depth of water in the southern part of the Adriatic, together with the clearness of the water, make this region one specially adapted to the search for submarines by aircraft and to the pursuit of submarines by hunting groups of surface vessels.


Strength and disposition.—The following enumeration of ships is subject to change and correction, owing to new dispositions that are made from time to time, but is sufficiently accurate for our present purposes.

French vessels in the vicinity of the Adriatic:

7 dreadnoughts.
7 predreadnoughts.
4 armored cruisers.
24 destroyers.
14 submarines.
8 auxiliary cruisers.

Italian vessels in the vicinity of the Adriatic:

5 dreadnoughts.
4 predreadnoughts.
5 armored cruisers.
4 light cruisers.
14 destroyers.
24 torpedo boats.
14 submarines.

British vessels in the vicinity of the Adriatic:

5 light cruisers.
5 monitors.
6 destroyers.
91 net drifters.
6 trawlers.

There is a force near the entrance to the Dardanelles sufficient to contain any surface vessels that may issue from Constantinople.

Courses of action open to us.—It is well to repeat the mission of the allied naval forces as a preliminary to the consideration of methods of accomplishing that mission.

“To obtain subsurface command of the sea while still retain command of the surface of the sea.”

The attainment of the subsurface command of the sea is of immediate and paramount importance to the allied forces. Victory or


defeat depend upon the solution of this problem. Submarines have sunk 12,000,000 tons of merchant shipping since the beginning of the war, and destruction continues at a rate of about 500,000 tons per month. At least 30 per cent of all sinkings occur in the Mediterranean. The effect of the shortage of shipping is apparent on the whole allied land front from the North Sea to Mesopotamia. This effect is increasing daily.

In considering the effect of a continued loss of tonnage on the general situation, we have to consider specially the critical situation in the Adriatic and the important adverse influence that is bound to be felt should these sinkings continue unabated. It would appear that the political situation in the Adriatic is such as to demand that extraordinary effort be made to revive a confidence in both the military and civil forces that victory will eventually rest with the Italian forces in that region.

So far the naval effort has been defensive, except for occasional brushes with enemy submarines. There has been no decisive and inspiring naval effort at naval offensive. There has never been a time in the conduct of the present war when the inauguration of an offensive was more needed than now. Their barrage operations in the Otranto Straits have failed completely to check enemy submarine operations throughout the Mediterranean. It would appear that some new form of effort must be undertaken if we are to accomplish the mission which has been laid down.

In considering any new form of naval effort in the Adriatic we must bear in mind the great advantage accruing to a concentration of effort and a unity of action. The Allies and the United States are handicapped by the lack of a central direction of political, naval, and military effort, and by the difficulties of coordination incident to the differences of language, views, and political aims, as well as by a lack of common doctrines of war; so that one of the problems in the local Adriatic situation is to remove, so far as may be possible, the difficulties indicated above by an organization of command, and by foreseeing and arranging for the difficulties likely to be encountered.

The courses of action open to us fall under four general heads:

(1) Reduction of enemy bases in the Adriatic.

(2) Destruction of enemy naval forces in their bases.

(3) Destruction of enemy naval forces at sea, either in the Adriatic or the Mediterranean.

(4) The containing of the enemy forces in the Adriatic.

(1) Destruction of enemy bases.—The only means of destroying enemy bases by naval forces is by bombardment, either at short or long range, depending upon circumstances. Assuming that it is not practicable to carry on simultaneously bombardment operations


against the enemy bases in the Adriatic, we have to consider the various bases with a view to determining which of these should receive first attention, should bombardment or other form of naval attack be decided upon.

Our mission requires that we do our utmost to obtain subsurface command of the sea. Cattaro is the base from which vessels operate to interfere with our obtaining the subsurface command of the sea. It is the base which is nearest to the lines of communication which we desire to protect, and one within which the largest number of submarines, destroyers, and light cruisers may be found.

It is so situated geographically that if we occupy a position to the north, enemy forces operating from Cattaro might be denied the support of their larger surface vessels based on Pola, which support, under special circumstances, might be essential to the operation of submarines from Cattaro.

We have already seen that the communications of Cattaro are inadequate for the support of large operations, either military or naval, should the water communication of Cattaro with northern Adriatic bases be interrupted.

We have also seen that the land communication of Cattaro lies in the near vicinity of the shore and is at several points exposed to attack by raiding forces. The above considerations indicate the desirability of devoting our first attention to this base, if any base whatever is to be the objective of naval and military operations. In deciding whether or not to make an effort either direct or indirect on Cattaro, we have to consider first that the only other method of accomplishing our mission is the containing of enemy forces in the Adriatic. Effort of this kind has been continued during the war without success. We are therefore compelled to adopt a method of either a direct or indirect attack on enemy bases.

A study of geographical conditions in the eastern Adriatic has already indicated to us the detached position of Cattaro, and has suggested the desirability of occupying a position north of Cattaro with surface forces superior to those of the enemy based on Cattaro. It should be thoroughly understood that such a line of action must be undertaken with vigor and with a decided superiority of force, in order to insure a success. Half-hearted measures are better not undertaken at all.

The occupation of a position north of Cattaro is not sufficient in itself to interrupt sea communication. We have therefore to consider what other means would be essential to interrupt completely sea communication with Cattaro. A mine barrage appears to be the most effective method of controlling a narrow area of the sea, provided it can be supported by the patrol of surface craft. We


should therefore consider in the selection of our base a position adapted to the support of a mine barrage across the Adriatic. On account of the depth of water no position south of the line Gargano Head-Curzola Island can be used for a continuous barrage from shore to shore. We might consider a partial barrage of anchored mines in the Otranto region, connected by a floating barrage, but experience to date has not warranted an expectation that the floating barrage would be effective. We would therefore be compelled to rely for the effectiveness of a barrage in the Otranto region on the patrol of the gap between the ends of the inshore mine fields. The depth of water in this region and proximity to the enemy base at Cattaro do not justify an expectation that such an effort would be effective.

In addition to the line Gargano Head-Curzola Island there is a second position which might be considered as available for barrage operations, namely, the line Nuovo Point-Grossa Island. The line Gargano Head-Curzola Island is about 130 miles nearer to the bases which it would be necessary to use for the mining force. Moreover, the adoption of the northern line would tend to scatter our efforts over a larger portion of the Adriatic, without thereby increasing the efficiency of that effort. The southern line is in close proximity to what appears to be a very convenient anchorage between the Curzola Island and Sabbioncello Peninsula, capable of easy and quick defense against both sea and land attack. The decision, therefore, is to seize this base as a preliminary to further operations.

The land communications of Cattaro should be interrupted at the same time that the base is seized. Apparently this can be accomplished by a raiding expedition, landing at the same time, in the same vicinity, but on the mainland. This expedition should be equipped especially for the expeditious destruction of bridges, tunnels, and the railroads so far as possible, and should be prepared to retire, when so compelled, upon the Sabbioncello Peninsula, and thereafter form the permanent holding force on that peninsula. As fast as resources permit, land and sea effort should be directed against the occupation of Lissa, Lesina, Brazza, and Meleda Islands. Independently of the military value of occupying these islands, the effect of public opinion in Austria would be most beneficial to our cause.

As soon as possible after the occupation of the base at Curzola, the laying of the mine barrage should be undertaken. The successful completion of the barrage would separate the entire northern Adriatic from the Mediterranean. There would then remain the problem of dealing with Cattaro; undoubtedly enemy operations would continue from that base until their supplies were exhausted.


Cattaro may be attacked—

(1) By air raids.

(2) By land attack.

(3) By a mine barrage encircling entrance to the port.

(4) By raids of surface vessels.

Air attack is supplementary to other forms of attack, and does not interfere with them. We can not expect great results from air attack until there is a pronounced concentration and continuity of effort in this form of attack. It is therefore desirable that immediately succeeding the land operations against Cattaro, there should be a continued operation of aircraft against Cattaro of the greatest possible strength, diverting aircraft from other employments to this one employment until the desired result is achieved. It appears that there are about 150 seaplanes available on the Italian coast—there are no doubt considerable numbers of land machines capable of bombing operations.

In designing air attacks it will no doubt be found desirable to time the original attacks in such a manner as not to cause a dispersal within the harbor of enemy craft previous to any bombardment and raid by surface vessels that is to be undertaken. It is desirable that future bombing operations be provided for by the manufacture of large numbers of bombing machines and by the manufacture of the necessary supporting fighting machines. The United States should participate in this effort. As the destruction of ship yards, dry docks, etc., is possible if undertaken on an adequate scale, an intensive campaign by aircraft gives promise of success against Pola, Fiume, and Trieste. Pola suggests itself as the first base to be attacked after the Cattaro situation is cleared up.

The land attack on Cattaro would involve such large forces and give such doubtful promise of success that the problem is merely suggested.

Any mine barrage about the entrance to the harbor of Cattaro to be effective would have to rest its two ends on the enemy shores and would have to be defended there by land forces. Difficulties of such an operation are very great and not considered practicable under present conditions. Occasional mine fields may be laid as traps for submarines and surface craft basing on Cattaro. A raid on Cattaro by surface vessels, if successful, would have a more profound morale effect on the general situation in the Adriatic than any other single operation can have, as it would indicate a change of attitude on the part of naval forces that might be most disturbing to the enemy. The approaches to Cattaro are not difficult from a navigational standpoint. Batteries are undoubtedly strong enough to resist any attempt of bombardment from the sea, but are probably not strong enough to prevent the running of the batteries at night. The tactical


problem involved is somewhat intricate and difficult, but the advantage of success would be so great that the risk of four or five battleships with the necessary sweepers and destroyers, is more than counterbalanced by the possible results that they could achieve.

It is suggested that the morale effect of a raid on Cattaro would be increased if it were made by American forces, as the advent of fresh forces in a region is always discouraging to the enemy, and especially so if their advent is coupled with a change of attitude from the defensive to the offensive.

Auxiliary to the mine barrage and to the various forms of attack on Cattaro there will necessarily be patrol operations and submarine hunting group operations to interfere, so far as possible, with enemy submarines still attempting to operate from the Adriatic.

Recent development of submarine listening devices enables listening vessels to hear surface vessels and determine their direction when they are within a range of 20 miles, either night or day. This development in itself is a great advantage, since raids on patrol craft in the Otranto region have heretofore been made by surface vessels coming out of Cattaro at night undetected, delivering their attack, and returning before there can be a gun attack of surface vessels. With the new listening device, it should no longer be possible for these operations to occur if listening vessels are properly stationed. Immediately a surface vessel is heard at night, our surface forces should take up a position between the enemy surface vessels and their base. Thereafter the problem is one purely of relative strength and relative tactical skill of the enemy forces and our own. Further, listening devices for the detection of enemy submarines have been perfected to such an extent that it will be very difficult for them to issue through narrow waters without detection, if vessels are properly stationed. In waters like the English Channel, where enemy submarines may go to the bottom and remain quiet, the use of listening devices is less efficient than in waters like the Straits of Otranto, where submarines are compelled to keep going, and thereby betray their presence, their course, and direction to the hunting groups. It is true that submarines may ground close to the shore in the Otranto region, but such action can be rendered extremely dangerous by the planting of deep mine fields as traps.

Whatever forms of operation are decided upon in the Adriatic there must be continued a constant patrol and hunting of submarines issuing from or returning to the Adriatic, until such time as the major measures which we take there shall have excluded submarines from that area. The greatest immediate step that can be taken in increasing the efficiency of patrol operations is the fitting of all suitable patrol craft with the most modern listening devices and the arming of those craft with weapons of such a nature that they may—


(1) Cope successfully with submerged submarines that may be discovered.

(2) Prevent submarines that are submerged from coming to the surface and escaping by superior speed.

(3) Defend themselves against the gun attack of submarines operating on the surface.

All patrol operations should be augmented so far as practicable by aircraft patrol, with the exception that no aircraft specially suited for bombing operations directed against enemy bases should be diverted to patrol operations. Supplementary to the patrol operations and the operations of hunting groups of vessels fitted with listening equipment, there should be operations by allied submarines in areas restricted to their exclusive use. The allotment of areas to various types of vessels and the coordination of patrol efforts is a semi-tactical problem that can best be left for solution to the senior naval officer in the Adriatic region.

General estimate of vessels required.—4 dreadnoughts; 10 predreadnoughts; 20 light cruisers; destroyers; trawlers and sweepers; submarines, listening groups, mine layers, transports, and auxiliaries; 30,000 troops.

System of command.—In the Adriatic theater the success of operations in which forces of several allied nations are necessarily engaged requires the most careful consideration and agreement in advance with regard to the allocation of tasks and responsibility, as well as agreement as to the higher command. Success positively demands that the combined international forces, afloat and ashore, engaged directly in the execution of the plan above outlined, shall be specifically under the command of a single naval officer. In general, the tasks should be assigned according to the facilities available for each nation, and care should be exercised that these tasks harmonize with the war aims and special interest of participating powers.

With regard to the allocation of tasks, the Italians are best able to conduct air raids, but in this they should be assisted as much as possible by all other nations. The Italians are better able to supply troops quickly in landing operations in Adriatic waters. The landing of such troops will also harmonize with the war aims and general policies of Italy. The other Allies might well reinforce Italian troops by any special troops which they have that have been trained in landing operations; for instance, American marines.

The proximity of Italy to the theater of operation requires also that she render the assistance at her command with respect to the mining bases and mining operations. She would naturally be charged with the convoy of her own troop transports and supply ships. The nation to which is allotted the laying of the mine barrage should control the surface defense of that barrage and should be


charged with preventing surface raiders from escaping through it to the Mediterranean. The barrage command naturally includes the command of supporting points of the barrage, such as Pelagosa Island, Gazza Island, Lagosta Island, and the defenses of the base at Curzola Island.

The proximity of Italy to the theater of operations requires also power in the Mediterranean, should supply battleships for naval raids upon enemy bases. The United States should furnish and transport the necessary mines for that portion of the barrage assigned to United States forces and should be in charge of the shore mine bases. The United States should also furnish listening devices of American pattern, together with personnel for operating them and as many patrol boats as can be spared from other areas.


(1) To seize and secure a base between Curzola Island and Sabbioncello Peninsula.

(2) Simultaneously with the seizure of the base, to raid the railroad in its vicinity, destroying tunnels and bridges, and occupying a position astride the road as long as possible. When compelled to retire from this position the forces to retire on Sabbioncello Peninsula and thereafter hold it permanently.

(3) To place sufficient naval forces at Curzola Island to interrupt completely all traffic of surface vessels between northern Adriatic bases and Cattaro.

(4) When troops and transports become available, to seize and hold the islands of Lissa, Brazza, Lesina, Lagosta, Meleda, Gazza, Pelagosa.

(5) To fortify Agosta Island, Gazza Island, Pelagosa Island, so that light vessels patrolling in this region may find refuge from attack under the guns of these islands.

(6) To lay a mine barrage from the Italian coast to Curzola Island, and to support this barrage by vessels based on Curzola Island and Brindisi.

(7) To organize and carry out as a surprise attack a raid on Cattaro which shall have for its mission the sinking of all enemy vessels in the harbor, provided subsequent information indicates conditions to be such as to warrant the effort.

(8) To assign immediately areas of operation for the patrol of the southern Adriatic, the mission of the patrol being to make it increasingly difficult for the exit and entrance of enemy submarines in the Adriatic.

(9) To equip the maximum possible number of patrol vessels with efficient listening devices, and to arm them in a manner suitable to their employment.


(10) To assign the general command of all these operations to a single naval officer of one of the cooperating powers.

(11) To assign the task of the raid on Cattaro to the American battleships, supported by such sweepers and destroyers of other nations as are best suited to the task.

(12) To carry on a continuous air attack on Cattaro and the vessels basing there. For this purpose to concentrate a maximum possible number of suitable aircraft.

(13) To hold a force of surface vessels in readiness at Corfu sufficient in strength to prevent the escape of enemy cruisers from the Adriatic.

(14) In directing the air offensive to concentrate first on Cattaro and then successively on the ports at which most enemy submarines may be building or may be harbored.

(15) To augment patrol effort by all available aircraft not specially suited to the attack of enemy bases. To select mining bases after consultation with the Italian authorities.

(16) To plant special mine fields as submarine traps in the vicinity of Cattaro, but to do this subsequent to the raid.

2 February, 1918.


Subject: Memorandum No. 9, dated 30 January, 1918.

In the original memorandum the matter quoted below followed the paragraph ending “War aims and special interests of participating powers.”

It is believed that there are no suspicions on the part of any nation in Europe, hostile or friendly, that the United States has any ambitions or intentions looking toward a foothold in Europe or its vicinity, or that she has any ulterior motives whatever in prosecuting the present war. The sole aim of the United States at present, is that the war shall be won as speedily as possible. It is therefore suggested that an American commander in chief for the joint forces engaged afloat and ashore in the Adriatic special operations that have been outlined, could best assure that cordial and energetic cooperation of the forces engaged that is essential to success.

The detail of on American admiral to this post would also have a more pronounced naval effect than would the appointment of an admiral of any other nationality. Such effect would be favorable to us not only in the enemy countries of Austria and Germany, where the feeling that the weight of the United States was now being exerted in the war would take hold, but also in Italy, where a similar feeling is desirable to assist Italian morale in regaining its former high standard.

In the original memorandum the “Decisions” (p. 74) included a decision—

To assign the general command of all these operations to an American naval officer.


I have thought it best to omit the above quoted matter from the copies of the memorandum as circulated and to introduce the proposals they contain in another way.

[Extract from Memorandum No. 71, "History of Planning Section."]

MEMORANDA NOS. 9 (30 JANUARY, 1918), 16 (7 MARCH), 31 (27 MAY), 37 (17 JUNE), 53 (23 SEPTEMBER).

Subject: “Situation in the Mediterranean.”

Memorandum No. 9 was initiated by the Planning Section as being the most important special problem at that time requiring solution after examination had been made of the general naval situation as a whole.

After reaching a solution on 30 January, 1918, the Planning Section was so much impressed with the importance of undertaking without delay the tentative decisions reached that it obtained permission of the Force Commander to endeavor to get the paper before the Inter-Allied Council at its next meeting, to be held soon after in Rome.

Under the. rules of the Council, however, the subject was presented too late for consideration at that session and consequently discussion of it by the Inter-Allied Council was postponed until the session which met in London on March 12. A decision was then reached approving the paper, but inasmuch as execution of the plan required military assistance, reference to the military representatives of the Versailles Council was necessary before allocation of the required troops could tie obtained.

By that time the military situation in France had become so grave that the Versailles Council decided no troops could be spared then. However, a subcommittee of the Council, including among its members Capt. H. E. Yarnell and Col. R. H. Dunlap, both of the United States Planning Section, met in Rome on 15 May and prepared detailed plans.

Meantime a mobile floating barrage across the Otranto Straits had been instituted and the laying of a net mine barrage continued slowly. These measures were moderately successful, but did net appear to be, nor likely to become, a satisfactory solution of the submarine situation in the Mediterranean.

By May, 1918, it appeared unlikely that any troops could be spared for a considerable time for the Sabbioncello operation; so the Planning Section again undertook a solution of the submarine situation in the Mediterranean on a purely naval basis. During the preliminary consideration of the subject, cablegram was received from Operations suggesting the Cape Bon-Sicily mine barrage.

On 17 June formal solution (P. S. Memo. 37) was submitted to the Force Commander, who brought the subject to the attention of the Admiralty.

On 23 July an emergency meeting of the Inter-Allied Council was held in London to consider mining operations in the Mediterranean. Capts. N. C. Twining and F. H. Schofield, both of the Planning Section, represented the United States at this meeting.

On 23 July, previous to the Council meeting, the Planning Section prepared a digest of its solution to the Mediterranean problem (P. S. Memo. 37). This was submitted to the Inter-Allied Council (see Council files No. 168), where it received consideration at the emergency meeting.

The Council approved the principles affecting mine barrages in general, and decided to request a commission at Malta, then studying various matters in connection with the Mediterranean mining operations, to examine in detail the definite proposals made by the United States for Mediterranean barrages.


Rear Admiral Joseph Strauss, U. S. N. commanding the United States Mine Force in European Waters, was appointed as United States representative to attend the conference at Malta, and took with him a complete copy of Planning Section Memorandum No. 37 to present to the Malta conference.

After Admiral Strauss's departure from London a cablegram was received from the United States Navy Department directing him to support the Cape Bon-Sicily project

The Malta conference adopted the general features of the United States proposal contained in Planning Section Memorandum No. 37, so far as they related to mining (sec report of conference—Inter-Allied file No. 188).

On 15 September, at the next meeting of the Inter-Allied Naval Council, the report, of the Malta conference was approved in general. Our proposal to continue plans for the Sabbioncello barrage was rejected.

The history of Mediterranean mining plans illustrates several important points.

I. The inherent difficulty of allied operations.—Definite conclusions were reached on 30 January, 1918, as to important active operations which should have been undertaken promptly in the Mediterranean against the enemy submarine campaign.

Authoritative and concrete decision to undertake them was not reached finally until 15 September.

In the early stages of the conference the Italians were not prepared to accept the United States proposals, and there was an undercurrent of Italian opposition throughout, apparently due to political jealousy. Some delay was caused, also, by the inability of the military command to provide necessary military support when asked for, though an earlier request might have received favorable action. But the principal cause for delay was the cumbersome method adopted for coordinating the naval effort of the Allies. A permanent council, similar to the Versailles Military Council, probably would have been able to insure prompter decisions and more timely coordinate action.

II. The need for close cooperation between Navy and Army planning.—Had the Navy planners been sufficiently informed continuously of the military situation in this case to know the probabilities of obtaining military assistance in the Adriatic, they would have been able to have adopted its naval plans accordingly. Similarly, the Army would have been able to plan with greater facility with respect to new lines of supply in the Mediterranean, about which inquiries were made during the period under discussion. It appears important that Army and Navy planners should be located near enough together to permit ready conferences.

III. The great importance of the planning function within a naval organization.—As far as known, the American solutions of the Mediterranean problems, together with others, including their estimate of the general naval situation, are the only comprehensive estimates made by any allied naval staff. This is remarkable, particularly in view of the lateness of the entry of America into the war. The allied naval strategy was formulated almost invariably by men burdened with war administration, who concerned themselves chiefly with questions most pressing from an administrative point of view. Even after the British Admiralty instituted a Plans Division the former method was continued and the Plans Division had little influence upon the broad aspect of the war.

In consequence, allied naval strategy in the main was the child of expediency. It lacked comprehensiveness, continuity, and oftentimes even soundness.


Memorandum No. 10.


30 January, 1918.



(See Map No. 5, “The North Atlantic Ocean.”)

General situation: As at present.

Special situation: Germany has seven completed cruiser submarines in commission. They are of the converted mercantile type; radius of action, 17,000 miles at 6 knots. Armament, two 5.9-inch guns, two 22-pounders, six inboard torpedo tubes. Speed, 11 1/2 knots on the surface; 8 knots submerged.

Germany is building twelve cruiser submarines, having a speed of 10 to 18 1/2 knots on the surface, 9 to 10 knots submerged; cruising radius about 20,000 miles. Armament, two 5.9-inch guns, two 4.1-inch guns, or four 4.7-inch guns; eight inboard torpedo tubes. The first of these vessels will probably be commissioned shortly and all should be in service by August, 1918.

Required: Estimate as to the probable employment of these vessels and the measures that should be taken in consequence.

Estimate of the Situation.

Our special and immediate naval mission in this war is—

“To obtain subsurface command of the sea while still retaining command of the surface of the sea.”

The problem with which we are dealing is but a special phase of the general antisubmarine problem, so that no statement of the mission other than the general mission need be made in the solution of this problem.


In examining the probable intentions of the enemy, we have first of all to consider the mission imposed upon his naval forces by his situation and its importance. The war that the enemy is waging is a land war: he must succeed on land if he is to dictate the terms of peace. In order to dictate the terms of peace he must break down the will of his strongest enemies, and his strongest enemies are on the


western and on the Italian fronts. If he succeeds on both of these fronts he will win the war.

From the beginning of the war the enemy has realized that the great effort of his enemies on the western and on the Italian fronts had to be supported by way of the sea. He has organized the support of his own forces and directed his own land strategy so that he can do without sea communications outside the Atlantic.

His basic naval mission has therefore been—

“To give the maximum support to his land forces in obtaining a successful decision on land.”

The special features of his strategic position and the relative strength of his own and enemy surface forces have caused him to conclude that he could best support his land forces by naval effort if he concentrated that effort on—

“The maximum possible sustained attack on the sea communications of the Allies.”

There can be no question that the above mission is the governing one of his active naval forces to-day and it will continue to be their governing mission.

The enemy cruiser submarines now under consideration are, or will be, a part of his active naval forces and will share in the enemy’s attempt at the accomplishment of this mission, viz:

“The maximum possible sustained attack on the sea communications of the Allies.”

We are sufficiently familiar with the character of the enemy to determine that he understands and practices the doctrine of concentration of effort. He has done this so long that it now is a part of his nature—a habit from which he does not avoidably depart. Offside effort is no part of his plan. We may therefore expect that the enemy cruiser-submarines will reinforce to the maximum degree possible the present submarine campaign which the enemy is carrying on. We have then solely to consider what areas will be most profitable for the operation of these vessels. Success of enemy submarine operations is measured, first, by quantity of tonnage sunk; and, second, by the character of the tonnage. There are three classes of things that come over the sea to support allied operations in France and Italy and these are: Food, munitions, men. At present the greatest need is for food because of the unfavorable reflex action that the scarcity of food exerts on the civil populations, thereby tending to break down the will to win. Food is now coming principally from two sources—South America and North America.

The building of the enemy submarines of the type under discussion in itself indicates determination to operate over wider areas of the sea, and to be able to remain away from base longer than heretofore.


So far unrestricted submarine warfare has been limited to zones declared by Germany.

On account of the general arming of merchant vessels and the consequent difficulty that submarines will encounter in boarding merchant vessels for visit and search, even in distant areas, we may be certain that Germany will—

(1) Operate in present declared zones; or

(2) Declare new zones; or

(3) Make a declaration that all the high seas are barred zones.

In other words, Germany will not submit her cruiser-submarines to the practice which has now become dangerous to submarines, to visit and search, previous to the sinking of vessels. German submarine warfare to date has been limited so closely to the barred zones as to indicate a firm policy on the part of Germany to use these zones in accordance with her declaration and not to carry the same class of warfare into unannounced zones.

The lack of tactical handiness of the submarine-cruisers, especially when submerged and when submerging, will prevent the cruiser-submarines from operating in crowded waters where they are liable to the sudden attack of surface craft or aircraft. The cruiser-submarine will naturally avoid convoys on the high seas if they are accompanied by fighting vessels of greater tactical handiness or greater gun power; it will avoid shallow waters. As it is designed for operating a long time without returning to base, it will naturally seek, other things being equal, an area of operations in which it may find an opportunity of refuge or a convenient bottoming ground. It will naturally be attracted by localities in which it may make occasional captures of vessels, may replenish its fuel and provision supplies. Since it is designed to operate for long periods at sea, it will trust more to the gun attack than to any other form of attack, as it can carry sufficient munition to attack more ships in this way than by any other method. Secondary to the gun attack will be the torpedo attack—the mine attack by cruiser-submarines is such an unprofitable form of attack in distant areas that it can be treated as a negligible quantity, requiring no unusual precautions.

A large quantity of grain comes from South America about this time of year, so that it will be natural to suppose that for the present the operations of cruiser-submarines should be directed against South American trade as well as against South African trade, in or near the zones of the Azores, and of the Cape Verde Islands. When the South American trade becomes of less importance and the North American trade becomes of great importance, we may expect a shifting of the area of operations of cruiser-submarines to the western Atlantic, as far south as the Gulf of Mexico and the Caribbean. The present situation on the American coast in the Gulf and in the


Caribbean Sea is one not calculated to give great concern to enemy operations in that region. Further, the appearance in that region of enemy submarines the enemy knows would tend to encourage the dispersal of our naval effort, with consequent loss in the general efficiency with which the war was being conducted. Political conditions at present indicate that the enemy has refrained from unnecessarily molesting trade on the American coast, in order that American public opinion would be in a more receptive mood for advances such as those recently made by the Austrian Prime Minister. By May or June of this year, the political situation should have cleared up sufficiently to enable the enemy to judge whether it is any longer profitable for him to refrain from operations in the western Atlantic, which, from a strictly naval and military standpoint, promise to be the most profitable to him. It would appear that the trend of events will convince the enemy that he must use his maximum power to interfere with the support America is giving the Allies without curtailing his present submarine effort near the focal areas on the coasts of Great Britain, France, and Italy.


As the principal effort of the enemy cruiser-submarines will probably be to sink tonnage by the use of guns, our principal concern should be in methods to defeat that effort.

His cruiser-submarines are to be armed with a battery far superior to that of the average merchant ship of to-day. The only merchant vessels carrying a battery sufficient to cope with the enemy cruiser-submarine are auxiliary cruisers and American transports; the latter class of vessel should, when loaded with troops, never be required to engage cruiser-submarine except while escaping his attack.

These conditions compel the adoption of the convoy and escort system in order that a sufficient number of guns may be assembled to be an adequate reply to the gun attack of the cruiser-submarine. It is doubtful if the guns and the guns’ crews assigned to the average merchant ship (American merchant vessels excluded) are adequate to cope with the gun attack of an enemy submarine, unless the convoy is more numerous than it has so far been expedient to make it. In other words, a special ocean escort will always be necessary to guard against the gun attack of the cruiser-submarine.

A general extension of the system of ocean escorts to traffic in the North and South Atlantic will probably eventually require more ocean escort vessels than could be made available unless battleships were used. A 1arge number of merchant vessels of various types are now on the stocks in both England and America will be available in increasing numbers. To meet the probable shortage of


ocean escort and to decrease the demand for nonproductive fuel at stations where it is supplied would require the obligation of ocean tonnage, it is suggested that certain of these merchant vessels be given a special armament of not less than four high-powered guns, with a complete trained gun’s crew for each gun, all under the command of a competent naval officer.

Vessels so armed would remain in the carrying trade and would be available for use as ocean escorts of convoys throughout their voyage. If the war continues for a considerable time still, the tendency will be toward the constant regrouping of commercial traffic to the end that vessels of similar speeds may be grouped in the same convoy, so that the loss now incident to requiring fast vessels to proceed in slow convoys will be largely eliminated. This regrouping of vessels will probably entail an increase in the number of convoys, with consequent increased demand for ocean escorts. Demand for increased zone escorts of destroyers may possible be met by the increased production of destroyers, but more likely by the lessened activity of enemy submarines in narrow waters should measures now under way prove successful, as torpedo attacks by cruiser-submarines in distant waters are more difficult to deal with than the gun attack, since the type of vessel best suited to ward off torpedo attack does not exist in sufficient numbers to permit its employment in any but focal areas. Security for vessels on the high seas against torpedo attack of cruiser-submarines must be obtained through increased precautions, rather than through escort by destroyers. If the time ever comes when we have enough destroyers and when they have sufficient cruising radius, it will doubtless be advisable to furnish one or two destroyers to accompany each convoy through the areas of cruiser-submarine operations, in order that they not only may guard the convoy against attack but may convert themselves immediately upon a submarine attack into a hunting group that shall thereafter pursue the submarine which made the attack to its destruction.


In considering the measures that may be taken against the enemy submarine we conclude that—

(а) The maximum possible effort should be made to destroy the enemy cruiser-submarine when it leaves or returns to its base.

(b) That when it causes losses of sufficient gravity in distant areas the system of convoy and ocean escort should be put into effect in that area until the threat disappears.

(c) That when sufficient destroyers become available without undue neglect of the focal areas or without departing from the policy of hunting groups, one or two destroyers might be assigned to each important ocean convoy, which destroyers would convert


themselves into a hunting group immediately when contact with enemy cruiser-submarine was obtained.

(d) That no destroyers now operating in European waters should be sent in distant areas at present because of the enemy cruiser-submarine threat.

(e) That merchant ships to be armed in the future be given one and if possible two 5-inch or 6-inch high-powered guns.

(f) That selected merchant vessels in proportion to about 1 vessel in 10 should be specially armed with four 5-inch or 6-inch guns and specially manned with full gun’s crews for each gun, under command of a competent naval officer.

(g) That the organization for placing into effect ocean escort system in areas likely to be areas of submarine-cruiser operations should be perfected at once and that suitable dispositions of ocean escort vessels should be made in readiness for instituting extension of the convoy and ocean escort system.

(h) That merchant vessels specially armed with four or more high-powered guns should also be given a special long-range radio equipment.

(i) That the extension of the present system of radio warnings by means of land stations be made so as to cover the maximum possible area and thereby enable the direction of shipping at sea.

(j) To organize hunting groups of submarines based on the American coast in readiness for operation against any enemy submarines that may visit these waters.


Memorandum No. 11.


13 February, 1918.



General situation: War as usual. Our maximum antisubmarine effort can not be developed for several months.

Special situation: The Allies and the United States decide to make the best possible psychological use of situations and events to strengthen the morale of their civil and military forces, and to weaken the morale of enemy civil and military forces—especially the morale of enemy submarine personnel.

Required: Estimate of the situation and decisions.

General Considerations.

The world’s mind—the mind of both friend and enemy—has reached a condition of acute tension. Civil populations in all the countries at war are beginning to doubt the wisdom of fighting longer. Popular wills are in unstable equilibrium. There is no longer the fixity of purpose that characterized the earlier stages of the war. Colossal events and extraordinary effort have dazed understanding and shaken faith, until now the hope of all whose understanding is clouded, and whose faith is not firm, is a return to peace in the hope that antebellum conditions will come with peace. These symptoms are forerunners of a breakdown in national wills.

War is fundamentally an attack on national will power. A war is won when—and not before—the enemy’s will is broken.

We are confronted now with a great opportunity and a highly dangerous menace, both of which reside in the minds of men. This opportunity and this menace is the increased suggestibility of the masses, due to the spiritual tension of their present state.

As a rule, we have sought to break the enemy's will by physical means exclusively, by the acts of physical war, leaving those acts to work as they might for or against us. We have failed to marshal and to organize the impressions of events as real forces in the war. We have concentrated on the physical and have neglected the spiritual elements of war. Under present conditions, the marshaling of


morale against morale is as worthy an employment of national genius as can be found. We can not place too much emphasis on the mission in this problem.


“To strengthen our own morale and weaken that of the enemy by psychological means, so as to give the maximum support to physical effort”


The enemy forces to be considered are the brains of the best civil and military psychologists that the enemy possesses, reinforced by a system of publicity and by a system of financial propaganda which, in the magnitude of their accomplishments, is second only to the great accomplishment of their war machine. These special forces have been in operation for years. The strength of these special forces is not found in their numbers, but in the skill and persistency of the few individuals who direct enemy psychological effort throughout the world. The skill of the individuals lies in their ability to understand and to predict the effects of events on the mind and character of the people; to shape impressions of events so as to influence the masses in a predetermined direction; to readjust facts in support of their own morale; and to invent reports and rumours suited to the breaking down of our morale.

Instances of enemy offensive in this direction are—

(a) The propaganda work in Russia.

(b) The purchase of Russian leaders.

(c) Propaganda work in Italy.

(d) Propaganda work in the United States, by which he fosters so far as possible the belief that American assistance is not needed in Europe; this campaign is falling through.

(e) Air raids.

(f) Propaganda in Spain and Scandinavia.

(g) Extravagant claims regarding loss of shipping.

On the psychological defensive the enemy—

(a) Persistently minimizes actual and prospective efforts of the United States in support of the war.

(b) Withholds information of his submarine losses; we assist him in this.

(c) Carries on a constant campaign of encouragement for both his army and civil population.

Notwithstanding a strong socialist party, food shortage, economic depression, and general war weariness, the psychological skill of the enemy has succeeded in holding his people well in hand, and in


making them believe they will win. Recent strikes and mutinies indicate a weakening of enemy morale, which, however, is not yet at the breaking point.

In addition to the forces that are active against us through enemy intention, there are influences within our own control that march favorably to enemy ends; some of these influences are—

(a) New hardships to our own civil populations, such as food rationing, fear of food shortages, high prices.

(b) Lack of knowledge of current events by civil populations.

Note.—War aims are not stated in simple personal terms understood by all—probably not more than 1 person in 10 can tell what we are fighting for. News is suppressed to such an extent that there is perpetual fear of the unknown. Even now rumors of extreme shortage of fond gain credence among educated people. The things that are accomplished, the difficulties that are overcome successfully and creditably, receive scant notice in the press because of censorship or other reasons.

(c) The general military situation in France and Italy, which causes the public to lose hope of material success on the western front in the near future.

(d) The long duration of the war, and consequent apathy of those who did not hear the roar of battle.

(e) Lack of imagination by many people in high places, and consequent sluggishness of mind that may follow.

(f) The dissatisfaction of labor with existing conditions.

(g) The public belief that America may not support the war soon enough.

(h) The belief that we are not holding the submarines.

(i) Pernicious activity of socialists and labor unions, and the resulting distrust and unrest—partly the result of German propaganda.

(j) Suspicion of discrimination in food distribution.

These and many other adverse conditions demand attention.

There can be no doubt that the attitude toward unfavorable conditions, even when those conditions grow no worse, is now one of augmenting dissatisfaction.

There can be no doubt that enemy intentions are to continue to use every means known to his psychologists to improve his morale and to weaken ours.


Now, when sufficient physical force to win the war is coming within our grasp, is the time to stiffen our own morale and to attack the morale of the enemy. With every country at war (except America) war weary, we must be sure that no collapse of the people's will shall cause defeat on the eve of victory.


The passive attitude toward psychological considerations must give way to an active campaign that shall meet every enemy move and anticipate him whenever possible. Brains must work to their utmost; character must stand stancher than ever; sacrifices must be made even more willingly than in the past. Confidence, the basis of morale, must be restored. The determination for victory must weld our efforts into unity. These steps require expert direction. The experience and success of our enemies suggest we employ the best psychologists to formulate a psychological policy, to draw up rules for applying the policy, and to instruct subordinates in the application of these rules and in the principles that underlie them. The proposed organization of psychologists should be in close touch, through designated individuals of the organization, with the people of all classes and with all departments of the Allied Governments, so that they may be constantly in a position to meet and solve problems concerning influence of events on the minds and characters of the masses. Psychological conditions are not permanent, nor are they restricted to any one phase of activity. The setting of each problem of morale changes from day to day, and so requires a ceaseless attention. No great problem should receive final solution without full consideration from the standpoint of mass psychology.

Auxiliary to the main international organization above indicated, there should be national committees giving attention to the problems of each country at war. No attempt will be made here to indicate how these committees should be subdivided or organized.

The immediate general problems confronting psychologists are—

(a) The arousing of a new enthusiasm for the war.

(b) The reestablishment of belief in the soundness of the Allied Governments.

(c) The reestablishment of confidence in the truth of what is published.

(d) The instruction of all, from the highest to the lowest mentalities, in the reasons why we are fighting.

Note.—these reasons should be reiterated from day to day, with illustrative incidents and discussion to make the fact plain and convincing to people of every profession, trade, and occupation that the personal interest of each individual is hound up in victory; that a peace by compromise means economic slavery, low wages, German domination, German commercial reprisals—a shamefaced existence for generations.

(e) A revival of interest in the smaller events of the war.

Note.—We venture to suggest that war news should immediately take on a personal aspect—that names of officers and men at the front should always figure in dispatches, and that all news items should carry with them the atmosphere of the battle held and the consequent picture of the supreme sacrifice that is a matter of daily occurrence along the entire front. The sufferings of friends, and pride in their deeds, will stimulate the determination to win.


(f) The uniting of all classes in a common purpose and determination to support the Government’s efforts toward victory.

Note.—The word “Propaganda” should not be applied to any effort which we make or are going to make. This word has taken on a sinister meaning of deceit and corruption to such an extent that statements issued from or efforts made by a minister of propaganda are discredited in advance.

The problem of the psychologists is not alone to build up our own morale, but also to attack the enemy morale. The points of weakness seem now to be in Turkey, Bulgaria, and Austria. It appears a propitious time to detach Turkey from her alliance. We suggest—

(1) The reestablishment of diplomatic relations between Turkey and the United States.

(2) The negotiations by the United States for a peace between Turkey and the Allies, special means being adopted to bring this about at the earliest possible date.

The question of indirectly assailing the morale of enemy submarine crews through such means as the press requires special treatment. A committee of naval officers with submarine experience or knowledge should be formed to devote their exclusive attention to the problem. They should have all advice and assistance from the psychology and publicity committees.

To affect directly the submarine morale requires naval effort, which can be exerted in the following forms:

(a) Hunting to the maximum possible degree with available hunting forces. They must be not only active, but also persistent whenever contact is made.

(b) Hunting by destroyers assigned to convoy work whenever at sea and not actually engaged in escort duty. When proceeding to sea to pick up convoys, and when returning to port after dropping them, destroyers may deploy so as to sweep a large area.

(c) By making the maximum offensive effort possible at every contact with an enemy submarine. For example, whenever a convoy is attacked, several destroyers may abandon their escort duty and make an intensified depth-charge attack on the submarine, remaining in the vicinity several hours, if necessary, hunting.

(d) A liberal use of depth charges on all contacts, even though the submarine position may not be known accurately, will disturb the enemy morale, as it is difficult to estimate the distance off of an exploding depth charge.

(e) By periodically scouting at night over areas probably used by submarines for charging batteries under cover of darkness. The middle of the Channel and of the Irish Sea are areas probably utilized for this purpose.


(f) By spreading rumors of new devices effective against the submarine; harrowing circumstances connected with submarines destroyed; numerous losses of submarines, etc.


(1) To organize commissions of psychologists in each country and to provide for the systematic association of these commissions in order that they may—

(a) Study and solve the specific problems already enumerated.

(b) Advise the several departments of their respective Governments on current problems of a similar nature.

(c) Organize publicity campaigns of education and truth, so that the people may understand thoroughly existing conditions and the reasons for a continuance of the war.

(d) Devise means for making the maximum possible use of events to break down enemy morale.

(2) To organize a psychological commission, consisting largely of naval officers, to give special attention to the question of enemy submarine personnel, with a view to determining how the morale of this personnel can best be attacked.

Bending the organization of these commissions, it will be necessary to take steps to achieve the objects already indicated. We suggest the following notes for consideration:

A. One of the present difficulties of our situation is to provide a mental diversion from the hardships of war, and at the same time an influence that will stimulate patriotism and loyalty.

Suggestion: To make a concerted attempt at a religious revival, the mission of the revival (aside from its religious aspects) being the support of the State through the stimulated conscience and loyalty of individuals. As a means of carrying out this suggestion, we suggest—

(1) The sending of Billy Sunday to England, and the support of his efforts by a carefully organized press campaign.

(2) The sending of other American and English evangelists on a similar mission.

(3) (1) and (2) above should appear under religious auspices and not under political auspices.

B. Another difficulty of our situation is lack of a thorough understanding and appreciation on the part of the English, the French, and the Italian people of the magnitude of the efforts that America is undertaking in the present war. Statements by the press do not convince the working people as thoroughly as they should. To make these statements more convincing and more vivid, we suggest—

(1) That Colonel Roosevelt visit the principal manufacturing centers of Great Britain, France, and Italy to address the work-


men. This would require the invitation of the Allied Governments and the hearty approval of the President of the United States.

(2) That other qualified Americans (and especially great labor leaders of America) join in this campaign.

C. The people of England are accustomed to the leadership of the King. We think that possibly the influence of the King’s leadership would be greater and more stimulating were he to occupy field headquarters in France. It would seem that such an action on his part would stimulate greater devotion of the civilian population.

D. The question of food is now uppermost in the minds of a very large number of people in Great Britain. It appears that the working classes are prepared to accept hardship, provided they feel that the food shortage does not fall more heavily on them than on others. It is presumed that this question is receiving careful attention; but we suggest that concrete instances of the equitable division of food be a matter of daily comment in the press. The impression prevails that the rich get meat, butter, and sugar in larger quantities than the poor, whereas the reverse is the truth. This fact should receive constant prominence in the press.

E. The morale of the enemy submarine personnel has stood the silence treatment for three years, and probably can continue to stand that treatment. We suggest that a change in policy be made, as follows:

(1) To publish broadcast and frequently general statements concerning the submarines lost and missing in comparison with the number of submarines operating or afloat.

(2) The publication of the details of sinkings of enemy submarines, together with the attendant circumstances that would most influence the fear of the personnel.

(3) The publication of scientific advances made in the detection of submarines when submerged.

(4) The publication of veiled references to new inventions that will destroy submarines when cruising submerged on soundings.

(5) The distribution of leaflets containing information of this character in the enemy country—by aircraft.

[Extract from Memorandum No. 71. “History of Planning Section."]

Subject: "Morale—Allied and Enemy"

This problem was set itself by the Planning Section at a time when the morale of the European allied civil populations appeared to be on the verge of some impairment.

The solution was circulated by the Force Commander among a large number of prominent British persons, including Lord Northcliffe. It was received very favorably and is believed to have been of utility in Great Britain.

It is understood that, the paper proved of considerable value to the United States Bureau of Public Information, at Washington, D. C.


Memorandum No. 12.


[A. Remarks by Commander United States Naval Aviation Force.—B. Remarks by British Plans Division.—C. Remarks by British Officer in Admiralty.]

15 February, 1918.

(See Maps Nos. 1, 3, and 6.)



General situation: War as at present. United States naval air effort still in its initial stages.

Required: The policy that should govern further developments of United States naval air effort in European waters.

The following decisions have been arrived at in the study of the aircraft situation, which follows:

Preliminary Decisions.


1. To make our primary air effort a continuous bombing offensive against enemy bases, avoiding sporadic offensives.

2. To make our secondary air effort a patrol in readiness for tactical offensive.

3. To depend principally upon kite balloons for patrol and escort work.


4. To concentrate our principal air effort in the Felixstowe-Dunkirk area in sufficient force to get local control of the air.

5. To direct all air effort we may make in the Adriatic against enemy bases in succession, choosing areas to fit conditions.

6. To make our patrol areas, whether patrol be by flying boats or by kite balloons, coincident with the operating areas of our surface vessels, with the greatest effort where shipping is most numerous.

7. To plan and build for our air effort against the Helgoland area.



8. To abandon the dirigible for use in European waters.

9. To concentrate our efforts on bombing machines capable of—

(a) Great radius of action.

(b) All-around defensive fire.

(c) Carrying the heaviest bombs.

(d) Efficient radio work.

(e) Efficient navigation.

10. To build fighters as necessary to get air control in the Felixstowe-Ostend area.

Note.—In fighters and bombers we should endeavor to outclass the enemy.

11. To build kite balloons for patrol and escort work.

Auxiliary Decisions.

12. To build air stations that are difficult of access to enemy aircraft, and where great effort in a congested area is planned to scatter aerodromes in small units.

13. To build kite balloon stations at the bases of the vessels that are to use the kite balloons.

14. In the distribution of preliminary resources and preliminary effort to give our principal attention to the Felixstowe-Dunkirk area.

15. To build as few types of aircraft as possible.

16. To consider the abandonment of flying boat type of aircraft for bombing attack on enemy bases and as fighters over narrow waters.

17. To continue the seaplane stations already authorized, but to use them as auxiliaries of bombing effort against shore objectives.

18. To equip present seaplane stations with machines suitable for use in bombing enemy bases.



In the general estimate of the situation submitted by the Planning Section on January 21, 1918, it was shown that the special conditions at sea in the present state of the war imposed upon the Navy as its principal and immediate mission—

“To obtain subsurface command of the sea while still retaining command of the surface of the sea.”

The investigation of naval aircraft effort that follows is based wholly upon the above-quoted mission, which mission imposes the following mission for United States naval aircraft in European waters:

Mission.—To render the maximum possible support to the antisubmarine effort.



The enemy forces to be considered in this problem are enemy submarines and, in special localities, enemy aircraft and enemy antiaircraft batteries. The numbers and types of enemy submarines are well known and will not be discussed. The intention of submarines can be fairly well predicted from their past performances. In bad weather they operate in the lee of the land, as far as possible. The English Channel, the Irish Sea, and the south coast of Ireland are favorite hunting grounds during the winter months. During the summer months they extend their operations well to seaward and south into the Bay of Biscay. The east coast of England and Scotland and all parts of the Mediterranean Sea are operating areas throughout the entire year;

As for enemy aircraft we know that they have air superiority in the east part of the North Sea from Dunkirk north.

Enemy antiaircraft batteries compel an ever-increasing altitude in flying.


Courses open to us.—We shall consider first that the courses open to us are uninfluenced by steps already taken by us. Then we shall consider what influence steps already taken will exert on decisions.

There are three types of antisubmarine air effort:

1. Patrol in readiness for tactical offensive.

2. Escort in readiness for tactical offensive.

3. Attack of enemy bases by bombing.


The object of patrol is first of all to sight the submarine and then—

(a) To attack.

(b) To report its position.

(c) To make the submarine submerge if it is in the vicinity of shipping.

The attack so far has failed because bombs have been too small and too few, and because the submarine gets ample warning and submerges. The latter reason is one which may not be avoided, so that we may expect the attack of submarines by aircraft to fail in the great majority of cases. In shallow, narrow waters that submarines must pass, the aircraft attack has its greatest opportunity.


In examining a large number of cases of attack, we have found that the first bomb dropped is the one most apt to do damage and that subsequent bombs that are dropped do not have the same chance of being effective. For this reason big bombs should be carried so that the most favorable opportunity will not be lost through the bomb being too small. Some German reports refer contemptuously to the effect of small bombs as fleabites.

The reporting of submarines is an important function of aircraft on patrol. Heretofore this function has not been exercised efficiently. It should be the principal field of usefulness of aircraft of all kinds that are on patrol. The prompt reporting and the efficient use of information gained by aircraft requires—

(1) Expert radio work by aircraft.

(2) Good navigation by aircraft.

(3) An organization to receive aircraft messages and to act upon them at once. Such action to be—

(a) To warn shipping.

(b) To send antisubmarine craft in pursuit.

The third function of aircraft on patrol is to keep the submarine submerged. This function will not be of any great use except in the presence of shipping. At sea, if the submarine submerges, all trace of it is lost, and the aircraft is bound, in the absence of landmarks, to lose track of the locality. The submarine will then resume operation without inconvenience.

Patrol may be by—

(a) Heavier-than-air machines.

(b) Dirigibles, both rigid and nonrigid.

The positive effect of patrol is measured best by the submarines that have been sunk by aircraft.1

From August, 1914, to December 31, 1917, there were one sure and six probable sinkings by aircraft, all types included. Not more than half the probable sinkings are really sinkings, so we may say that aircraft have not sunk over one submarine per year.

Aircraft patrol may give information of enemy submarines. Records of performance in this line indicate that many sightings occur without any real advantage to us—this on account of—

(a) Difficulty of communication.

(b) Absence of patrol craft in vicinity.

(c) Absence of merchant vessels in vicinity.

(d) Inaccuracies of aerial navigation.

Patrolling for information that is not actually used is wasted effort. Use the information or else do not go after it.


1 Comment by section member: "Not altogether.”


During July, August, September, October, and November, 1917, British naval aircraft—

Heavier-than-air type:  
Flew 360,000 miles.
Sighted 74 submarines.
Attacked 50 submarines.
Average length of flight 124 miles.
Average flight distance to sight a submarine 4,740 miles.
Flew 262,981 miles.
Sighted 16 submarines.
Attacked 9 submarines.
Average, length of flight 146 miles.
Average flight distance to sight a submarine— 16,346 miles.

From these figures we see that seaplanes and flying boats are about four times more efficient per mile of flight in sighting submarines than dirigibles. Attacks of submarines sighted may be neglected, since all were unsuccessful. It is obvious, however, that the dirigible is more vulnerable, more unwieldy, and less fitted for attack. Both types are about equally safe for personnel. Navigational difficulties are about equal in both types.

As to patrol, then, we conclude—

(1) To abandon the dirigible type.

(2) To concentrate our efforts on the heavier-than-air type, and to equip this type with large bombs and with efficient radio and navigational equipment, so that all submarines sighted may be reported without delay.

(3) To organize a radio service in connection with aircraft patrol.

(4) To coordinate air and surface patrols.


Escort duty for aircraft appears attractive because of the fact that the aircraft can see, and because also submarines submerge on sighting aircraft, thereby giving up the great tactical advantage of maneuvering on the surface to a favorable position for attack. When, however, we examine the possibilities of escort duty by aircraft, we find—

(a) The average speed of convoys less than 10 knots.

(b) The average speed of aircraft over four times as great.

(c) The average flight period of aircraft less than three hours.

(d) That aircraft are restricted to operations near shore.

(e) That aircraft fly in good weather when submarines operate off shore, and that when submarines are driven inshore by bad weather, aircraft can not operate efficiently.

(f) That for escort duty the efficient range of aircraft does not exceed 30 miles with slow convoys and 50 miles with fast convoys, unless relays are used.


(g) That although dirigibles once they are in the air are more suitable for escort duty—as lookouts—than heavier-than-air craft are, the advantage they possess is not sufficient to justify their existence when other employments are considered.

(h) That the kite balloon (discussed later) is a more satisfactory solution of the escort problem.

We conclude as to escort duty that neither dirigibles nor heavier-than-air machines should be designed for this duty, although they may be employed as escorts on special occasions.


The third employment for naval aircraft is the attack of enemy bases. The arguments for such attack are so well known as to need little discussion. Bases arc certain to contain submarines. Their location is known exactly; the destruction of bases destroys the submarines’ ability to operate. The points for attack are few, permitting concentration of effort.

The attack of bases is a pure offensive effort. Palliative efforts against submarines have failed, and are continuing to fail.

In the attack of bases capacity of aircraft for useful load is a prime requisite. This requirement is directly in line with the requirement for patrol and escort efforts. We have studied many reports on all forms of air effort and conclude from them that—

(1) Our primary air effort should be offensive against enemy bases.

(2) Our secondary air effort should be patrol for information, in readiness for the tactical offensive.


The natural areas of the massing of resources to carry on an air offensive against enemy bases are the east of England and the east of Italy, the localities nearest to enemy submarine bases.

The relative importance of patrol effort in various areas is indicated in the following:

Seaplanes and airplanes.

Average flight to sight a submarine, all stations 5,335
Dundee 12,410
East coast 5,460
Yarmouth 7,800
Felixstowe 1,894
Westgate 5,415
Dover and Dunkirk 3,022
Portsmouth 7,280
Plymouth 6,841


From this it appears that the Felixstowe area is the most fertile of all fields for air patrol, and that the only other area comparable with it is the Dover and Dunkirk area. It is also of great strategic importance, since the exclusion of submarines from these areas would be a more important accomplishment than the exclusion of them from any other area of equal extent outside the Mediterranean. Further, if we are to undertake bombing operations against enemy bases, there are no bases in such easy reach as Ostend and Zeebrugge, which lie within the Felixstowe-Dover areas.

The important bases of Helgoland, Wilhelmshaven, Emden, Bremerhaven, Cuxhaven all lie within 300 miles of Felixstowe. No other point in England is more than 40 miles nearer to these bases than is Felixstowe. These facts indicate the great importance of an air concentration in these areas when judged solely from the naval standpoint; but when we realize that such air concentration is also on the immediate flank of the enemy land forces, the soundness of air concentration in this area becomes doubly evident.

Air operations in the Dunkirk area have so far been handicapped by enemy control of the air. The necessity the enemy is under of navigating his submarines through narrow, difficult waters—and through shallow waters in order to reach the Dover exit—makes control of the air for him an essential.

The aircraft problem, then, in this area is—

(1) To assemble at operating bases enough aircraft and personnel to give numerical superiority in the air at all times.

(2) To build machines adapted to the locality to be controlled— fighters with long radius of action and the most approved armament.

(3) To build bombers to attack enemy bases.


Kite balloons do not properly belong to an air-effort classification, but may be discussed here, as their influence is similar to and almost as effective in escort and patrol duty as the influence of aircraft.

Kite balloons in the five months for which preceding aircraft data are given—

Patrolled 40,334 miles.
Sighted 3 submarines
Average length of patrol 333 miles.
Average patrol distance to sight a submarine 13,445 miles.

In the sighting of submarines the kite balloon appears as efficient as dirigibles. The kite balloon offers certain advantages in escort work not possessed by other aircraft. Among those are:

(1) The distance patrolled equals the distance advanced by the convoy during daylight—fog neglected.


(2) A surface vessel can be directed with precision toward any object sighted.

(3) An efficient lookout can be kept, as basket is steady and no noise distracts attention.

(4) Information becomes instantly available to surface craft.

(5) Can operate in weather not suitable for other aircraft.

(6) Radius of action can be indefinitely increased by carrying booster charges. Weight of boosters equals about 1 ton per day of service.

The disadvantages of any lighter-than-air aircraft when escorting convoys is their visibility and the consequent guide they may be to submarines attempting to get in touch with the convoy. Careful investigation of the problem indicates that vessels in convoy escorted by two kite balloon vessels are three times as safe from attack as when they are not so escorted.

We decide therefore—

To use kite balloons for escort and patrol duty when practicable.

Kite balloon stations should be at bases for the naval vessels that are to use them, and not elsewhere.


Having decided to focus effort on two kinds of aircraft—the heavier-than-air and the kite balloons—we shall now consider what types should be developed, and what should be the tendency of further development.

There are two principal areas in which aircraft will operate:

(a) Where enemy aircraft may be met.

(b) Where enemy aircraft may not be met.

In both areas the capacity to carry useful load is of prime importance. In area (a) a part of the useful load must be devoted to armament which has for its missions the attack of enemy aircraft and defense against enemy aircraft. The final aircraft objective in every case is on land or on water, so that useful load must always be conserved to make the attack on the land or on the water as decisive as possible. These requirements can be met only in big machines. Big machines are unwieldy. They can not dodge the small fighter, so they must meet his attack in some other way. It would appear that all big machines should be designed for all-around fire and that they should plan for air actions on the basis of a minimum of maneuvering in the air. If their armament is powerful enough to keep enemy fighters at a distance they will go through to their objective—which is what we desire of them.


As we desire to attack distant points, and as we desire increased length of time in the air on each patrol—great radius of action—at least 1,000 miles is essential.

Preliminary Decisions.


1. To make our primary air effort a continuous bombing offensive against enemy bases, avoiding sporadic offensives.

2. To make our secondary air effort a patrol in readiness for tactical offensive.

3. To depend principally upon kite balloons for patrol and escort work.


4. To concentrate our principal air effort in the Felixstowe-Dunkirk area in sufficient force to get local control of the air.

5. To direct all air effort we may make in the Adriatic against enemy bases in succession, choosing areas to fit conditions.

6. To make our patrol areas, whether patrol be by flying boats or by kite balloons, coincident with the operating areas of our surface vessels, with the greatest effort where shipping is most numerous.

7. To plan and build for our air effort against the Helgoland area.


8. To abandon the dirigible for use in European waters.

9. To concentrate our efforts on bombing machines capable of—

(a) Great radius of action.

(b) All-around defensive fire.

(c) Carrying the heaviest bombs.

(d) Efficient radio work.

(e) Efficient navigation.

10. To build fighters as necessary to get air control in the Felixstowe-Ostend area.

Note.- In fighters and bombers we should endeavor to outclass the enemy.

11. To build kite balloons for patrol and escort work.

Auxiliary Decisions.

12. To build air stations that are difficult of access to enemy aircraft, and where great effort in a congested area is planned, to scatter aerodromes in small units.

13. To build kite balloon stations at the bases of the vessels that are to use the kite balloons.


14. In the distribution of preliminary resources and preliminary effort to give our principal attention to the Felixstowe-Dunkirk area.

15. To build as few types of aircraft as possible.

16. To consider the abandonment of flying-boat type of aircraft for bombing attack on enemy bases and as fighters over narrow waters.


The following air stations have been planned, and work on them is in hand:

Seaplane stations, France:
  Dunkirk, for 36 seaplanes.
Treguier, for 24 HS-1.
Aber Vrache, for 24 HS-1.
Brest, for 24 H-16.
Ile Tudy, for 24 HS-1.
Le Croisic, for 24 HS-1.
Fromentine, for 24 H-16.
St. Trojan, for 24 HS-1.
Arcachon, for 24 H-16.
Seaplane stations, Ireland:
  Bantry Bay, for 24 H-16.
Wexford, for 18 H-16.
Queenstown, for 24 H-16.
Lough Foyle, for 24 H-16.
Seaplane stations, England:
  Killingholme, for 30 H-16.

These stations cover both the north and south coasts of Ireland and the entire western coast of France from the English Channel south. The plan is to supply them with machines of the HS-1 and the H-16 types. None of the machines are yet in existence so far as known, so their qualities are not known with sufficient exactness to determine suitability for operations.

The above-mentioned distribution of air stations in France and Ireland indicates a dispersion of effort and an employment of aeroplanes in areas where their use can not be profitable.

The station at Dunkirk appears unnecessarily close to enemy lines, and, as the British have already been compelled to abandon their station there, we suggest the advisability of further consideration of this location with a view to its possible abandonment in favor of a position somewhat more retired. The stations above mentioned can be justified in part if the missions of aircraft operating from these stations are announced as—

(1) To prepare to operate against enemy bases and enemy aircraft.

(2) Search for and attack enemy submarines.


These missions, if accepted, require that aircraft assigned to stations already authorized shall be of a type suitable for operations in the Felixstowe-Ostend area, and suitable for bombing operations.

Dirigible stations, France:
Paimboeuf, for 2 dirigibles.
Rochefort, for 2 dirigibles.
Arcachon, for 2 dirigibles.
Guipavas, for 2 dirigibles.

Note.—As these stations have not yet been begun, we recommend that no work be done upon them.

Kite-balloon stations, France:



La Trinite.

Kite-balloon stations, Ireland:


Lough Swilly.

It is noted that the kite-balloon stations are not in all cases located at the operating bases of the vessels which are to use them. No American vessels are to operate from the north coast of Ireland.

As the experience gained by pilots in flying over the water from stations already authorized will be valuable in preparing them for bombing fights, and as the air patrol in these areas may be of some use, we do not recommend the abandonment of any stations, but that they be recognized as auxiliary to the bombing stations.

The preliminary decisions are therefore adhered to with the addition of the following decisions:

17. To continue the seaplane stations already authorized, but to use them as auxiliaries of bombing effort against shore objectives.

18. To equip present seaplane stations with machines suitable for use in bombing enemy bases.

A. Comments of Commander United States Naval Aviation Forces, Foreign Service.

The 18 decisions arrived at in this problem seem to cover completely the entire field of our aircraft situation in Europe; and, where disagreement with a decision is noted, a brief discussion is submitted.

No. 1. To make our primary air effort a continuous bombing offensive against enemy bases, avoiding sporadic offensives.

Agreed to.

It would be found in all probability that night bombing will be profitable, and also other aerial activities will be necessary to carry this out, such as bombing enemy aerodromes, photographing, and the necessary fighting machines to accompany them.


No. 2. To make our secondary air effort a patrol in readiness for tactical offensive.

Agreed to.

It must be remembered, however, that the patrol will surely drive the submarine offshore to a certain extent, which will render his task all the more difficult. We should not abandon the patrol, for we can not neglect to fight the submarine on his hunting ground simply because we are bombing him in his bases. This matter should be viewed from the standpoint of ships saved as well as submarines destroyed—the presence of patrol aircraft undoubtedly protects ships from submarines, as shown by the records. It is the belief of our organizations that we can destroy some submarines by air patrol craft, and although we are less effective on patrol than in bombing bases, we can not afford to abandon the patrol. It would seem to be wisest for us to be on the sea in force where our transports are navigating dangerous waters, whenever possible, which is another reason for patrol. To say that the positive effect of patrol is measured by the submarines destroyed is, we think, an entirely incorrect point of view. The better measure is by the number of ships saved—for that is the object of the patrol.

(Note.—The Planning Section was unable to obtain any data as to the positive effect of air patrol on the sinking of ships, and, therefore, adopted the somewhat less inclusive data of sinkings of submarines by aircraft.)

No. 3. To depend principally upon kite balloons for patrol and escort work.

Disagree with this in part.

Undoubtedly kite balloons are of value for patrol and escort work, but should not be the principal dependence. After all, they are only a very effective lookout station, and have no offensive value themselves. They betray the position of the convoy or patrol to the same extent as a dirigible, and much more so than do seaplanes. It is true that they have been very successful at a small outlay up to the present time, but it is possible that this success may be based on an incorrect estimate of their effectiveness by the enemy. At any rate the enemy have avoided attacking ships protected by kite balloons, but this may be said also in the case of seaplanes or dirigibles. Should we rely solely on kite balloons and the enemy find a method of successful attack, the result would be serious, and it is not certain that he may not discover after all that he has overestimated the value of kite balloons. In this connection it would be entirely feasible to carry out practical experiments to determine the comparative efficiency of kite balloons, dirigibles, and heavier-than-air craft in sighting submarines and attacking after discovery.


It is possible to establish kite balloon stations at all places from which destroyers are operating, and, to supply as many as are needed, leaving ample resources for the operation of other types.

(Note.—The Planning Section has not revised its decision regarding the usefulness of kite balloons for escort and patrol duties; but recognizes that with the data at hand, the difference between it and that of the Commander United States Naval Aviation Forces, Foreign Service, is one of opinion.)

No. 4. To concentrate our principal air effort in the Felixstowe-Dunkirk area in sufficient force to get local control of the air.

Agreed to.

A preliminary survey of the situation on the east coast of England should be made, with a view to establishing bases for bombing operations, especially in the Canterbury region. Bases on the southeast coast of England will probably be freer from molestation by the enemy than those in the Dunkirk area.

Our heavy bombing machines could be assembled at Pauillac and flown to their aerodromes in the same manner as those used in France.

No. 5. To direct all air effort we may make in the Adriatic against enemy bases in succession, choosing areas to lit conditions.

Agreed to.

No. 6. To make our patrol areas (whether patrol be by flying boats or kite balloons) coincident with the operating areas of our surface vessels, with the greatest effort where shipping is most numerous.

Agreed to.

No. 7. To plan and build for our air effort against the Helgoland area.

Agreed to.

Do not think this should be confined to Helgoland area.

(Note.—The Planning Section made recommendation No. 7 to plan and build for air effort against the Helgoland area specifically, because of the importance of that area; and because also it believed that whatever would be suitable type for that area would be a suitable type for any other probable operations.)

No. 8. To abandon the dirigible for use in European waters.

Not agreed to.

It would seem that the actual conditions of the coast of France have not been fully considered as a field of operation for the dirigible. It is very well to give preference to offensive operations; but where we have troop transports and supply vessels constantly making the French west coast ports, it is unsound to discard the dirigible— an instrument that certainly has merit from a defensive standpoint, as it can in certain weather go well out to sea and escort convoys into port. They can surely be of use on the coast in escort work with the coastal convoys; and, while probably not as effective in this as seaplanes, commanding officers of ships with whom I have talked


and who have been escorted by dirigibles always recommend them. It may be that the small dirigibles are lacking in offensive power as used in England, but those we propose to operate in France are larger and we believe more suitable for the purpose. The dirigibles we propose can carry on the average bombs up to 800 pounds, and provide an excellent field for the operation of radio as well as a comfortable lookout station for a large number of men. Their slow speed enables them to hover over any spot, keep rendezvous, and accompany convoys under advantageous conditions. Our dirigibles will be able to remain in the air 24 hours at slow speeds, and we hope to better to some extent the vulnerability to damage in bad weather by building more efficacious avant ports to our hangars.

To condemn dirigibles for lack of offensive powers and rely on kite balloons would seem to be a mistake, when a dirigible can do all that a kite balloon can and a great many things in addition—for example, cover the sea in a very efficient manner around a convoy and actually inflict damage on submarines, for it must be remembered that a submarine can not man his guns in the presence of a convoy. The French (who have had much experience in dirigibles and have developed an efficient type) prefer them to kite balloons.

(Note.—The Planning Section has not revised its opinion as to the principle of abandoning dirigibles for use in European waters; but on account of the partial engagements already entered into, considers it inadvisable to set aside the present program for dirigible stations. The Commander United States Naval Aviation Forces, Foreign Service, states that in deference to the opinions expressed by the Planning Section he is reducing the program for dirigibles one-half. The Planning Section therefore recommends that the determination of future policy regarding dirigibles be left open for the present, pending the accumulation of sufficient data regarding operations from the American stations now authorized.)

No. 9. To concentrate our efforts on bombing machines capable of—

(a) Great radius of action.

(b) All-around defensive fire.

(c) Carrying the heaviest bombs.

(d) Efficient radio work.

(e) Efficient navigation.

Agreed to.

No. 10. To build fighters as necessary to get air control in the Felixstowe-Ostend area.

Agreed to.

It is not believed that we can get control of the air in the Felixstowe-Ostend area by simply building fighters. Probably systematic bombing of aerodromes, with only sufficient fighters and photographing machines to do this effectively, is necessary.


No. 11. To build kite balloons for patrol and escort work.

Agreed to.

No. 12. To build air stations that are difficult of access to enemy aircraft, and where great effort in a congested area is planned, to scatter aerodromes in small units.

Agreed to.

Other means will also be necessary, such as the employment of lighters or floating bases, flying machines up to starting points as far forward as possible by daylight, and scattering machines and personnel as well as possible.

No. 13. To build kite balloon stations at the bases of the vessels that are to use kite balloons.

Agreed to.

This is being done in every case except Queenstown, and could easily be done there. Stations at present are located at La Trinite, La Pallice, Loch Swilly, and Berehaven.

No. 14. In the distribution of preliminary resources, and preliminary effort, to give our principal attention to the Felixstowe-Dunkirk area.

Agreed to.

It will be impossible at this time, because we can not get the type of machines from home at present, and our Allies can not spare them.

No. 15. To build as few types of aircraft as possible.

Agreed to.

No. 16. To consider the abandonment of flying boat type of aircraft for bombing attack on enemy bases and as fighters over narrow waters.

Agreed to.

It is probable that as seaplanes and flying boats are improved they will not only make more effective the patrol, but other uses will develop, such as carrying listening devices for use when on the water.

No. 17. To continue the seaplane stations already authorized, but to use them as auxiliaries of bombing effort against shore objectives.

Agreed to.

It must be clearly understood, however, that the seaplanes necessary for patrol will not be efficient for bombing operations. Patrol pilots will require special training for bombing against shore objectives, which can be given to a limited extent at the present seaplane bases. With these exceptions, the bases could be used to great advantage in organizing personnel and preparing for bombing against shore objectives.

No. 18. To equip present seaplane stations with machines suitable for use in bombing enemy bases.

Not agreed to.


This is impracticable at some of the stations where landing fields are not available. These stations, where possible, should have some of these machines, but only sufficient for personnel to become acquainted with the machine. Actual flying at night can be done as a practice. The seaplane stations have a distinct use in our antisubmarine campaign, and require a special type of seaplane for their work which is not suitable for bombing shore objectives. These stations should be retained as patrol stations, using them to assemble personnel for other operations where this can be done to advantage.

Note.—Regarding the specific recommendations made by the Commander United States Naval Aviation Forces, Foreign Service, the Planning Section understands that all the questions therein raised will be taken up under the direction of the force commander.

The following recommendations are submitted:

1. That the Planning Section consider this matter in England with the planners of the British Admiralty, inviting assistance from the French as to matters around Dunkirk and from the Italians as to matters in the Adriatic.

2. When the work to be undertaken has been decided on, the amount which each nation is to undertake should be determined by the Inter-Allied Aircraft Council or some committee of air representatives of the different nations.

3. When the work to be undertaken by us has been determined, our organization to then determine the types and numbers of machine to be used, after consultation with allied experts.

4. That the United States representatives consider different projects in the following order of importance:

(a) Concentrate in the southeast coast of England—Dunkirk area.

(b) Undertake operations against submarine bases in the Adriatic.

(c) Maintain a coastal patrol against submarines.

(d) Undertake operations against Helgoland or other enemy bases on the North Sea or in the Baltic.

In conclusion, the following comment on the paper of the Planning Section is set forth:

It would seem to me that this paper lays too much stress on the failure of air patrol to destroy submarines, and on page 93 it is stated that the reason of failure to destroy is because a submarine gets ample warning and submerges; this protects friendly shipping— the object of patrol.

The statement on page 94, that the positive effect of patrol is measured best by the submarines that have been sunk, I can not agree with, as it seems to me the best measure of patrol is the amount of protection afforded our own shipping. It can be positively stated that our aircraft patrol, when officially established, will be well


equipped both in materiel and personnel for reliable communication, and there is no reason why proper reports and information should not be forthcoming. Coordination of air and surface patrols should be perfected, as the air patrols are under the direct orders of the officers controlling the surface patrols.

The observations on aircraft which point out that the slow speed of the convoys is a disadvantage does not apply to the dirigible, but favors that form of aircraft.

The average flight of aircraft certainly should be increased much beyond 3 hours; in the case of dirigibles it should be beyond 10 hours.

It must be remembered that control of the air in the Dunkirk area will not prevent submarines from coming out at night; hence bombing operations are all the more desirable.

With reference to the statement on page 98, where it is indicated that vessels in convoy escorted by two kite balloons are three times as safe from attack as when they are not so escorted, would seem to apply equally well to dirigibles.

The statement on page 100 that the distribution of air stations in France and in Ireland indicates dispersion of effort, and the employment of airplanes, etc., for their use can not be profitable. I think remains to be proved. It would undoubtedly have been better could our air activities have been concentrated in one area, but such was not possible.

The view of the station at Dunkirk is correct, and many surveys have been made with a view to securing a better location. I was informed by the officers who selected this site that there was no other available place for seaplanes along the Channel in France. It is proposed to have another thorough search made and see if conditions can not be improved at Dunkirk immediately.

There is no kite balloon station in France at Mindin, but one stationed at La Pallice. With the exception of the station at Berehaven, it would seem that all the other kite balloon stations meet the requirements that they be located at the ports from which the vessels using them operate. It is true that we have no vessels operating from Loch Swilly, but it would appear that the English have, and this station, I believe, was located at this place to supply kite balloons to English destroyers.

B. Remarks by British Plans Division.

The comments made by the Commander United States Naval Aviation Forces, Foreign Section, on Problem No. 6, Memorandum No. 12. agree so closely with the views of the British Plans Division that they may be adopted practically in their entirety, and it is proposed to draw attention only to the few small points of divergence.


Decision 3.—It is considered that kite balloons, while effective for escort work, are not so suitable for patrol, and that antisubmarine patrol work should be carried out mainly by aircraft, both heavier and lighter than air.

Decision 4.—The Canterbury region, while most suitable for the German bases in Belgium, is not so well placed for long-distance bombing raids to German bases in the Bight, and it is considered that for these purposes the Felixstowe area is superior.

Decision 6.—It is considered that the most economical and effective use of patrols is to maintain sea lanes rather than to patrol wide areas. It is recognized, however, that this is a matter of operational arrangement, and that the distinction is largely a verbal one.

Decision 7.—The United States Planning Section’s remarks are concurred in.

As regards the other decisions, the remarks by the Commander United States Naval Aviation Forces, and his final comments, are concurred in.

C. Remarks by British Officer in Admiralty on Memorandum from the Force Commander, United States Navy.

(Policy Unit should govern development of United States naval effort in Europe.)

This memorandum is of great interest and should serve a useful purpose in calling into prominence certain large issues which affect the employment of naval aircraft in the present and near future. It is no detraction from the value of the paper that exception must be taken to some of the views expressed and conclusions reached.

In reviewing the arguments raised, it is proposed to state, in the first instance, the main issues of the present moment and to indicate their growth and relative importance; then to discuss each in relation to the points covered by the memorandum.


The assistance which can be given by aircraft to the antisubmarine effort falls broadly under three main headings:

(1) Attack on enemy submarine bases by aerial bombardment.

(2) Action to bar the passage of submarines through narrow or restricted waters which must be passed by the enemy.

(3) Defensive measures, including patrol and escort.

(1) Hitherto a bombing offensive against enemy bases has not been the primary effort of the Naval Air Service, though it is a subject, which has always received attention.

Three main objectives are offered for the attack—the German North Sea ports in the Helgoland Bight, the Belgian coast bases, and Austrian bases in the Adriatic.


In the first year of the war a bomb attack was carried but by seaplanes against Cuxhaven. but the weight of bombs dropped was insignificant; an attempt to renew this form of offensive indicated that little can be expected from the type of aircraft available when starting from ships in the open sea.

The idea of developing attacks on these bases has, however, always been kept in view, and a proposal to carry out a more extensive endeavor by large flying boats refueling at sea was considered in the latter part of the year 1916. At the present day the range of available aircraft still renders the problem difficult, but it is hoped to carry out attacks of some importance this year by utilizing towing lighters to convey the aircraft to within 100 miles of their objectives before a flight is commenced.

The objectives on the Belgian coast offer a much easier target, and it must be admitted that more might have been undertaken in this area than has actually been the case.

A long period elapsed before the possibilities of bombarding by aircraft were adequately realized, and it is due to this fact that various mistakes have been made such as the dispersion of force and lack of concentrated effort with the Handley Page machines, the first numbers of which were ready in November, 1916, and were sent to the eastern end of the western front in winter (where they were of little value), instead of being used against the important submarine objectives close at hand. Further, there have been long periods during which bombardment of the submarine objectives on this coast have been suspended by order; and again, the work of the forces available has been divided between attacks on naval objectives and points of military importance.

The opinion is held by many officers, and particularly by those best qualified to judge, that the submarine activity on the Belgian coast might have been affected adversely in no small measure if the whole naval bombing resources available in 1917 had been devoted to this single purpose.

Up to the present Great Britain has been unable to provide sufficient naval bombing aircraft to undertake attacks on the Austrian submarine bases in the Adriatic.

(2) The policy of attempting to close the channels through which the enemy’s submarines pass to the open sea, in which aircraft will take an important part, is one of comparatively recent date. The establishment of a barrage can only be rendered effective by a proper coordination of all arms, and in this respect the aircraft action must necessarily be dependent on the development of action by surface craft,


In the coming summer serious effort is to be made to close the Straits of Dover, the Straits of Otranto, and to hamper the passage of submarines passing to the Atlantic by the northern route between the Shetlands and Norway. It is essential to realize that where only a limited number of aircraft is available, better results may be anticipated from such work than can be expected in bombing attacks which necessitate the continuous employment of large forces.

(3) In considering defensive measures it should be remembered that with the craft available in the early stages of the war, patrols, in the vicinity of the coast were practically the only form of work which could be carried out. Up to the end of 1916 attempts were chiefly devoted to the question of reconnaissance flights to seaward in the North Sea, with a view of detecting movements of enemy surface vessels.

As the activities of enemy submarines became more serious every endeavor was made to provide improved defensive measures for the protection of the vast number of merchant ships proceeding along the eastern and southern coast of Great Britain. The work of aircraft in this connection has proved of great value and must be gauged by the number of ships which have been saved rather than by the number of submarines destroyed. The resources available have been comparatively small, averaging about 200 seaplanes and 50 airships in the course of the year 1917, and it is unquestionable that far better results have been obtained from these craft so employed than Would have been the case by an equivalent effort with contemporary craft expended on bombing of enemy bases.

Great progress has been made in improving the method and system of patrols, and experience of the last year has indicated the points at which stations are principally required; it may generally be said that the system is now in an advanced stage of development. Much yet remains to be effected as regards improvements in the intelligence and communications, but these matters are in hand, and when the organization is placed on a sound basis, when surface craft have developed the practical use of the hydrophone, and when the air units approved are completed to the establishments arranged, efficient protection should be afforded to shipping in coastal waters.

As an indication of the value of these palliative measures it should be realized that in the Portsmouth command, an area of approximately 9,000 square miles, with waters most suitable to submarine operations, there is a monthly traffic of 2,000 vessels passing east and west and a cross-channel traffic exceeding 600 per month, yet the average losses have not been above five ships per month in the last half year.


It would, of course, be erroneous to ascribe this success wholly to aircraft, but it is unquestionable that the comparatively small force available, roughly, 30 to 40 seaplanes and 6 airships, has contributed in a large measure to the success achieved.


Turning to the proposals contained in the memorandum from the force commander, the importance of maintaining aerial supremacy in the area described as Felixstowe-Ostend is fully agreed. The movements of submarines in these waters from bases on the Belgian coast are of great importance and can be interfered with by aircraft to a degree which can not be obtained by any other arm. In this respect excellent work has been done by large America sea planes operating from Felixstowe, and this has led to opposition on the part of the enemy, the first engagement between a large America and surface craft taking place in May, 1917. Numerous engagements have occurred since this date, and it is necessary to provide defense for these bombing sea planes; an attempt has been made to establish cooperation with the naval fighting machines at Dunkirk, but there is little doubt that the question will not be adequately dealt with until arrangements are made for two or three large Americas to proceed from Felixstowe in company, escorted by a flight of two-seater fighter machines of the De Haviland 4, or improved type.

It is the case that the enemy has been allowed to have too much control in this area and that he is in an ascendancy on the eastern side at the present moment. This state of affairs can only be altered by the employment of increased forces and a radical change in our system of control and administration. One centralized command, extending from the latitude of 53° north to the southward, must be established.

Note.—This small part of the North Sea, known to the enemy as De Hoofden, is essentially a single area from an operations point of view and it is remarkable that there is no expression in use in the British Navy to indicate it briefly. It is suggested that the term “Hinder Sea" should be employed.

On several occasions it has been suggested that the control of aircraft on the western seaboard of the Hinder Sea should he centralized, and that there should be a senior officer at Harwich controlling the naval units at Yarmouth, Harwich, and Westgate. Arrangements are already in progress to establish a main base intelligence office at Harwich to deal with all movements of craft in the Hinder Sea, and when effect is given to both these schemes a very great increase in efficiency may be expected.

With regard to the class of machine required for operations in such areas, where the enemy’s craft are to be encountered, a large machine


with great weight carrying capacity and all-round arc of defensive force is eminently desirable, but as experience has shown is by no means easy to achieve. For the present, requirements can be adequately met by the large America seaplane for antisubmarine bombing, provided it is escorted by land fighters as described above; working in cooperation the two types mutually support, each other, and in the event of engine failure over sea by one of the land machines, the crew can be saved by the seaplanes.

Looking to the future it is impossible to overstate the danger we are in of the work at Felixstowe suffering serious interference by heavy bombing attacks undertaken by the enemy; it is therefore considered advisable that in arranging for an increase of the fighting forces for this area attention should be paid to the alternative of utilizing land bombing machines operating from a base farther inland less liable to attack by enemy.

As to the forces which would be required to maintain an adequate superiority, it is far from easy to lay down any definite figures. To a considerable extent the enemy can choose his own time for the departure and arrival of submarines, and it is therefore necessary for the allied force to keep up a more or less continuous patrol of the area. The power of selecting a suitable time for undertaking an attack on the patrolling force with a concentrated force of lighting machines gives the enemy an initial advantage that is difficult to counter.


As already stated, arrangements are being made for attacks to be carried out by large Americas, operating from east coast ports, towed within striking distance of their objectives in special lighters. In view of the weight of bombs which can be carried and the special conditions required for this form of attack to take place, it can not be expected that the damage inflicted on the submarine objectives will be comparable to that possible in the case of the Belgian coast, where constant bombardments can be carried out from a shore base.

The possibilities of bombardment by bombing craft carried in ships has also been discussed and is considered impracticable. The main points involved in this question are as follows:

(a) Machines might be dispatched from carriers with flying decks and be compelled to land in the sea after the attack, the pilots being saved by destroyers or submarines.

(b) Longer range machines might be used; to be flown from ships within a hundred miles of the objective and after delivering the attack to fly back the full distance and land in England in the vicinity of Yarmouth.


(c) Machines to start from Norfolk, carry out the attack, flying the full distance to the objective and back.

Of these alternatives, (a) is considered out of the question as unduly wasteful of machines, which could be better employed in ordinary work elsewhere.

Both (a) and (b) involve large supporting forces of ships of the fleet, in which case the fact of fleet fuel consumption, etc., has to be taken into account.

In comparing (b) and (c) it is to be noticed that the difference is roughly a matter of flying an additional 140 miles, say 2 hours, or the equivalent of, roughly, 700 pounds weight in machines of the Handley Page type, approximately six 112-pound bombs. This addition to the length of flight is no light matter, but it is probable that the bombing machines of the near future will be able to fly such a distance and to carry an adequate weight of bombs, the saving which would be derived in avoiding the risk to ships of the fleet and in economizing in fuel must be given careful consideration when framing future policy.

It should be noted that the flight from Yarmouth is 108 miles over sea, after which the coast of Holland can be skirted, machines coming down in a neutral country in the event of engine failure, and in the case of Wilhelmshaven only the last 60 miles has to be flown over enemy territory.


As at present arranged this work is principally assigned to the Italian Air Force. Any additional force which can be supplied to supplement their efforts should prove of value.

Barrage work.—It is noticed that the memorandum makes no reference to barrage work at exits used by enemy submarines. As arrangements are well in hand for this work to be carried out by British aircraft at the three points of strategical importance, it is agreed that it would be better for American forces to be employed on other work.

Defensive work.—It is considered that the views expressed in the memorandum convey an inadequate appreciation of the value of patrol and escort work. As already stated, the criterion of success or failure is the number of ships saved rather than the number of enemy submarines destroyed. It is true that the results of attacks on enemy submarines have proved somewhat unsatisfactory, but though the number of cases of positive destruction are few, other cases are known in which damage has been caused, or the deflection of the submarines from the work in progress has occurred. Every endeavor is being made to increase the offensive power of patrol ma-


chines; the size of bomb has been raised from 100 pounds to 230 pounds, and it is hoped to increase to a weight of 320 pounds in the coming summer. At the same time great attention is being paid to the accuracy of bomb dropping, and it is reasonable to expect that cases of definite destruction will be more frequent in the year 1918. Experience has shown that patrols are specially useful in weather of low visibility, when the seaplane comes upon a submarine suddenly and the latter is unable to completely submerge before the attack is delivered.

Whatever statements may be made to the effect that the crews of the enemy’s boats regard aircraft attacks as of little importance, there can be no question that every endeavor is made to avoid such attacks, and in thick weather the enemy is in continuous danger of serious attack in any area where adequate patrols are carried out.

These patrols are, however, less important than convoy work, and it is considered that the memorandum is liable to give an erroneous impression of this important function of aircraft work. All experience tends to show that the presence of aircraft with a convoy acts as one of the greatest deterrents to submarine attacks, and in this respect no class of craft is superior to the small airships which are capable of a flight of 10 hours and can keep in station on a convoy whatever the speed. It is indisputable that a very considerable number of merchant vessels have been saved by the patrol airships, and on this account the employment of these craft is being extended in the fullest limits possible by the establishment of new stations and the employment of mooring-out positions. With heavier-than-air craft there is a difficulty as stated in the large difference in speed of the seaplane and the convoy, but it is found that great benefit is derived not only from machines flying with and around the convoy, but from the patrol of the traffic routes before the arrival of the convoy.

A word should be said in regard to kite balloons. It is recognized that the kite balloon is no more than a special lookout position in the carrying ship, and it is true that exceptional success has accompanied the employment of balloons up to the present. It may be, however, that this success is based on a false foundation in that the enemy, who has consistently avoided attacking ships with balloons in the past, and may find it probably easier than he anticipates when the increased number of kite-balloon ships will reduce the number of unprotected targets. Should a policy of solely relying on kite balloons for the protection of vessels in convoy be adopted, and should attacks prove successful, the result would be serious.

The airship is altogether superior to the kite balloon in that she is offensively armed, and when stationed to windward of the convoy


is in a position to reach any submarine seen, at a high speed, probably well over 60 miles an hour.

The decision to have no American airship stations is noted, and it is agreed that they should be unnecessary in the British Isles in view of the provision already made.

Great importance is attached to the American seaplane stations in course of preparation around the coast of Ireland and on the western coast of France, and it is considered that any diversion of the resources intended for this purpose would be a grave mistake.


1. To sum up: In view of the present arrangements for patrol of the more important areas and for aircraft to undertake the barrage work at the main exits, it is agreed that any further American naval aircraft can best be devoted to offensive operations against the enemy submarine bases.

2. The proposal to concentrate in the Felixstowe-Dunkirk area in sufficient, force to get local control of the area is considered sound and likely to lead to the enemy being compelled to suspend his submarine operations from the Belgian coast. This would be a great advantage, as the activities of the boats at present based on Belgium would be reduced to the extent of at least 50 per cent if driven north to the Helgoland Bight.

3. If sufficient aircraft can be provided for further operations, the Adriatic objective should next receive attention, the Helgoland Bight bases being ignored for the time being except in so far as present arrangements with large Americas from Harwich and Killingholme are concerned.

4. In considering types for use in areas where enemy aircraft are to be met, it is considered that a combination of fighters and bombers for daywork against submarines would prove more satisfactory than big machines with all-round fire.

5. Fully concur in the desirability of building air stations in positions difficult of access to enemy aircraft; to this end it may be necessary to have a main station well to the westward of London, using advanced aerodromes on the east coast for operations over the Hinder Sea.

[Extract from Memorandum No. 71, "History of Planning Section."]

Subject: “United States Naval Air Effort in European Waters."

This paper was initiated by the Planning Section.

In view of the comparative ignorance of the Planning Section of the technical side of aviation and its complete lack of aviation experience this solution was intended only as a preliminary study of the subject and the decisions only as tentative.


Notwithstanding the objections made by the Commander United States Naval Aviation Forces in Europe to some of the decisions, the action of the Planning Section in submitting the solution met with his enthusiastic approval. It resulted in his consulting the Planning Section frequently, when opportunity offered, and in the initiation of conferences between allied naval aviation representatives to determine the policies and principles which should govern their future joint action.

When demobilized the Planning Section was about to solve a problem to determine the policy that should govern the peace-time development of the Air Service for the Navy.

On 15 March the Force Commander forwarded this memorandum with the following comment:

“1. I forward herewith copy of the comments of the Commander United States Naval Aviation Forces, Foreign Service, on the Memorandum No. 12 of the Planning Section of my staff regarding aircraft, together with notes (in brackets) made by the Planning Section on the comments of the Commander United States Naval Aviation Forces, Foreign Service.

“2. The comments of the Commander United States Naval Aviation Forces, Foreign Service, are based upon a thorough study by his organization of all the questions raised by the Planning Section. Attention is invited to the close agreement of the Planning Section and the Commander United States Naval Aviation Forces, Foreign Service, on all the essential points of the air program.”


Memorandum No. 13.


23 February, 1918.

[Prepared at the suggestion of and in collaboration with Capt. R. H. Leigh. U. S. N., following a raid by the enemy against the Dover barrage patrol.]

(See Map No. 1, “The North Sea.")



General situation: As at present.

Special situation: Enemy forces are able to make surprise raids on Dover barrage forces at night.

Required: A plan for getting advance information of approach of enemy forces, so that they may always be met in superior force.


The solution that follows is based on the use of a recently perfected sound-detection device, the K. tube. No other methods are considered, as it is assumed that methods for preventing surprise not based on recent scientific developments have been fully considered and experimented with.

The K. tube is a microphone listening device, consisting of three microphone units so arranged and wired that the direction of any sound heard may be ascertained with reasonable accuracy.

K. tubes are particularly applicable for use—

(a) From drifting vessels.

(b) From vessels anchored in a tideway.

(c) From tripod stations on the bottom of the sea.

K. tubes used from drifting or anchored vessels are usually suspended about 70 feet below the surface of the water and are trailed two or three hundred feet from the vessel, in order that water noises may not interfere with listening.

K. tubes from an anchored or drifting vessel will indicate the direction of a sound with a probable error of 5° to 10°. K. tubes from stations anchored on the bottom of the sea should be of sufficient distance above the bottom to prevent any noises on the bottom interfering with listening. The directional qualities of anchored K. tubes are better than the directional qualities of K. tubes


trailed from vessels, as the errors of direction incident to trailing are entirely eliminated.

The K. tube’s efficiency is not interfered with by surface water noises, so that the state of the sea does not affect its sound-receiving qualities.

It is possible by the use of the K. tube to get the direction of at least three vessels at the same time when these vessels are on widely separated bearings.

The range of the K. tube depends largely upon the noise made by the vessel heard, which generally depends upon the speed of the vessel. The ability to hear vessels within range is seriously interfered with by local noises, such as own ship noises, so that the efficient use of the K. tube requires that own ship noises be reduced to a minimum. All machinery should be stopped during the listening period. It has been found by actual experiment in rough weather that an American submarine can be heard as follows:

Speed of submerged submarine: Distance (yards).
0.6 knots 2,500-3,000
2 knots 8,000-10,000
4 knots 15,000-20,000

At higher speeds the range is greater, vessels having been actually heard at a range of 26 miles.

The K. tube, when used from anchored or drifting vessels or from stations anchored on the bottom, is always ready for instant use. It requires no elaborate installation and no silent rooms at the listening stations. K. tubes used from anchored or drifting vessels require great care in observations taken when the vessel is drifting very slowly, or when the tide is slack, as at these times the K. tube may not tow with its head directly toward the vessel; but by a system of reciprocal sound hearings the error of K. tubes can be determined and applied in each such case. When a sound is heard, its hearing may be taken in less than one minute, and continuous bearings may be taken thereafter at any desired interval. A vessel with a high-speed engine can be readily distinguished from one of low speed, and a submerged submarine from one running on the surface.

In the case of K. tubes on tripods anchored on the bottom, the shore listening station or the ship listening station connected to the tube by cable may be at a distance not greater than 20 miles.

Having the above qualities of the K. tube in view, the following plan for its use in a sound barrage to the northward of Dover Straits is suggested (see British Admiralty Chart No. 1406):

(1) From North Foreland Lighthouse, on a line running east, true, place two anchored K. tubes—one at 10 miles, the other at 19 miles from the lighthouse; and on a line running N. 52 E., true, place a


third K. tube 18 miles from the lighthouse. Connect each of these K. tube stations by cable to a listening station in the lighthouse; connect the lighthouse by telephone to Dover.

(2) From Dunkirk Lighthouse on a line running north-northwest, true, place two anchored K. tubes—one at 11 1/2 miles and one at 19 miles from the lighthouse. On a line running N. 10. E., true, place a third K. tube 18 miles from the lighthouse. Connect these K. tube stations to a listening station in Dunkirk Lighthouse. Connect Dunkirk Lighthouse by telephone with the operating station for Dunkirk naval forces and with Dover naval forces.

In case it is impracticable to establish these listening stations at once, temporary arrangements may be made for listening stations in the same approximate localities by stationing monitors as listening stations for drifting K. tube sets. If monitors are used, it will be necessary for them to keep their machinery shut down, and to maintain quiet during a sufficient part of each hour to insure that timely notice of any vessels moving in the vicinity shall be given to the K. tube listeners.

Destroyers in making raids travel at high speed. The assumption that they will be heard when within 10 miles of the above outlined K. tube stations is conservative; the chance is great that they will be heard within 20 miles of these stations. When heard, their bearing can be easily determined, and by using the bearings obtained from different stations a correct idea can be reached as to their location, and by subsequent bearings their course and speed can be ascertained.

Taking the conservative estimate of 10 miles sound range from K. tube stations, the nearest approach the destroyers are likely to make to the Dover-Calais line before being heard would be 30 miles, from which an hour’s warning could be had of any raiding vessels under way for that line, thus giving ample time to withdraw drifters and other unprotected vessels, or to send a suitable armed force to meet the raiding vessels.

The one difficulty to be encountered in such a sound barrage as is proposed is sound interference. This can be minimized and more or less overcome as follows:

(a) By regulation of the hours in which shipping may pass through an area of 10 miles on each side of the sound barrage lines, thus making as nearly as possible a silent area.

(b) By limiting to a minimum the operation of British naval vessels in this area.

(c) By requiring British naval vessels which do operate in this area to stop their engines at given times for short intervals (five minutes).


The silent area desired in this case is not large, and there is at present little traffic in it. As raids are undertaken at night, it could be arranged so that ordinary shipping would pass through the silent area during daylight. At night there would be no great danger for British naval vessels which must operate in this area stopping their engines at given times, it being understood that in case of emergency the stop was not to be made.

An objection may be made to the sound barrage on the ground that there would be numerous false alarms, due to friendly vessels passing through this area. If the conditions outlined in the foregoing paragraph are complied with, there would be few false alarms, and even these could be materially reduced, if not altogether overcome, by a simple system of recognition signals. To make these signals would require no special devices on the vessels; taps with an ordinary hammer on the underwater hull is all that would be needed. Morse code could be used for this purpose, a specified letter or combination of letters to be made at a given time each day, at each specified time a different signal to be used. The signals would be changed daily as in the case of recognition signals.


Memorandum No. 14.

25 February, 1918.

[Initiated by the Planning Section in accordance with Decision 8 of the estimate of the general naval situation.]

(See Maps 1 and 3.)



The solution of this problem was undertaken from data available in London, and is submitted tentatively until opportunity is had to examine local conditions in the Channel and to consult data at Channel bases.


General situation: Enemy submarines continue to use the Straits of Dover as a passage between the North Sea and their operating areas in the English Channel and the Atlantic Ocean. During the month of December about 50 per cent of total merchant ship losses outside the Mediterranean occurred in the Channel. Most of the other losses occurred close to the shores of Great Britain and France.

Special situation: The Allies and the United States decide to deny passage through the Channel to enemy submarines, and to render the Channel safe for merchant ships.

Required: Estimate of the situation and plans for—

(a) Decreasing immediately losses in the English Channel.

(b) Denying the English Channel to enemy submarines while still permitting commercial traffic.

(c) Organization of channel command: cooperation of forces; convoy system with special reference to assembling from, and separation to, various ports of vessels of convoy.

Conclusions Reached in the Following Paper.

1. To unify the Channel command.

2. To man with American crews the present French antisubmarine Channel forces, exclusive of harbor defense craft.


3. When practicable to augment the present antisubmarine effort at Dover by—

(a) A mine barrage (deep and surface) from Kentish Knock to Dunkerque.

(b) A deep mine barrage from Hastings to Touquet Point.

(c) A system of ground listening devices operated from shore, located about 20 miles eastward of Dover Straits.

4. To organize immediately a continuous surface patrol east of line Start Point-Sept Isles, with a total force of 30 destroyers or P-boats, the patrol to be assisted by ground listening devices operated from shore, by air patrols, and by kite balloons.

5. To augment the above patrol by a series of deep mine fields; planting continuously in the usual areas of enemy operation until he abandons the Channel.

6. Until extensive deep mine fields can be laid, to employ a few hunting groups in the eastern Channel in conjunction with the patrols, and to develop tactics for “mining in” a bottomed submarine with deep mines.

7. To concentrate hunting effort west of the line Start Point-Sept Isles; and to assist this effort by deep mine fields and patrols in waters favorable to bottoming, off both Cornwall coasts.

8. To place orders immediately for 70,000 additional mines.

9. To increase the efficiency of the Channel convoy system by the following measures:

(a) Carrying a kite balloon on one ship of each escort.

(b) Placing convoys in a formation of wide front which decreases as the depth increases.

(c) Adopting a policy of determined depth-charge attack by several escorts against every attacking submarine.

(d) Arranging convoy sailings so as to avoid passage at night during moonlight.


(a) To decrease immediately shipping losses in the English Channel.

(b) To deny English Channel to enemy submarines, while still permitting commercial traffic.


Enemy submarines operate from the northern bases in general as follows:

Normally about 10 big submarines per month use the Channel for passage, going past Dover as a rule on the surface at H. W. slack, and during darkness. Lately this number has decreased, probably


due to the increased efficiency of the Dover barrage. They usually keep in the deep gut so as to facilitate diving.

There are generally 3 or 4 small U. B. or U. C. submarines from the Flanders Flotilla operating in the Channel: principally against overseas through-channel traffic, which normally brings them nearer to the English than the French coast. In bad weather they usually bottom in Lyme Bay, the Plymouth Bight, or other bights where sea is smooth. At night they probably cruise slowly at from 1 to 3 knots.

Strategic value of the Channel to the enemy.—The great focal area of shipping, lying in general between the south coast of Ireland and the French northwest ports, must continue to be the center of the enemy submarine effort, if his submarine campaign is to succeed. The distance to this area via the Channel is 480 miles from Zeebrugge and 660 miles from Helgoland. North-about via Fair Island these distances become 1,320 and 1,300 miles, respectively.

If passage through the Channel is denied, there will result a reduction of about 40 per cent in the number of small submarines that can be maintained in the focal area, and about 20 per cent in the case of the larger type.

Besides its value as a passage to and from the focal area, the Channel is also of immense value as an operating theater. Of all traffic to and from the United Kingdom, more than half passes through the Channel, exclusive of the vast crosswise traffic on military service. The Channel is itself a concentrated focal area, offering to the enemy the further advantage of narrow width, great length, and sheltered waters.

Moreover, cross-channel traffic is a vital link in the communications of the British Army in France.

The enemy’s probable intentions

1. The desire to reduce passage time and thus increase the number of boats operating, as well as to take advantage of good hunting en route, will persuade the enemy to proceed to station via the Channel unless it is too dangerous.

2. An enemy submarine operating in the Channel has two main problems to consider (mine-laying submarines not included).

(a) The problem of getting in touch with shipping.

(b) The problem of charging batteries.

As a rule, shipping keeps to the north side of the Channel, so that must be the operating area for submarines.

The submarine, to get into touch with merchant shipping during daylight, will keep a periscope watch when vessels are near, and will operate on the surface at other times. The submarine has always in mind the possibility of attack and plans to avoid attack by—

(a) Submerging and running.

(b) Bottoming.


The increasing ability of the antisubmarine craft to pursue submarines when submerged will increase the tendency of submarines to “bottom;” so that submarines will always prefer positions where water is less than 40 fathoms deep and the bottom is not rocky.

As listening devices become fitted to seagoing vessels, the danger to submarines operating off soundings will increase, possibly sufficiently to counterbalance the tendency to operate offshore during good weather; in other words, the operations of hunting groups may drive submarines to operate in narrow waters the year round. If this should be the case, it would be doubly important to make those waters highly dangerous for submarines.

3. The submarine fears—

(1) Destroyer attack.

(2) P-boat attack.

(3) Depth charge attack—any vessel.

(4) Aircraft attack.

(5) Deep mine fields.

In general, the avenue of escape from (1), (2), (3), and (4), above, might lead into danger of (5), particularly if the submarine were pursued. If, however, the submarine knew that there was real danger of (5), then its correct course should be to bottom immediately until danger has passed or until dark.

4. Undoubtedly submarines charge their batteries during daylight whenever possible to do so unobserved. At night they prefer to charge where there is small chance of interruption.

5. The geographical position of Cornwall, combined with shelter afforded on one coast or the other in almost all weathers, will make that immediate locality a desirable hunting ground for the enemy in rough weather.


The enumeration of our forces is omitted. They comprise numerous units for all varieties of antisubmarine effort, and are being increased constantly.

They are divided into six separate major commands, having no coordinating heads—three British and three French. Coordination between British and French forces is accomplished through their respective Governments. These conditions render it impossible to cope adequately with an enemy whose forces, by means of a flexible system of command, are enabled to conform quickly to changed conditions. For example, a group of submarines known to be operating just south of the Isle of Wight would be met only by our forces based on Portsmouth, while at the same time we might have large British and French forces in other near-by areas, some unemployed, in readiness, others operating in regions vacant of submarines.


While it is true that the various Channel commands are supposed to, and do, cooperate, the extent to which such coordination prevails necessarily depends upon the personalities of the respective district commanders and upon the cordiality of the relations existing between them. Furthermore, any commander will be reluctant to detach forces specifically assigned to him for the protection of a given area for duty elsewhere, unless the responsibility for such a move is taken by a senior.

Obviously the organization of our Channel forces prevents their employment in accordance with the best principles of warfare. Without unity of command our forces can not be operated with the necessary flexibility, nor be employed as a whole to the best advantage.

Our present Channel command is about to be further complicated by the addition of American vessels, thus introducing a third nationality in forces already suffering the handicap of two languages. It would be desirable to man with American crews the French antisubmarine forces (exclusive of those assigned to harbor defense) now operating in the Channel. Incidentally, this transfer would permit France to commission certain cruisers needed for ocean escort work, but laid up owing to luck of sufficient personnel.

The importance of denying passage through the Channel is heightened by the present plans for the Northern Barrage, which, if successfully completed while Dover remains unblocked, will prove a wasted effort and serve the enemy better than ourselves by forcing him to use the route most advantageous to him.

Owing to its narrowness, the Dover Strait appears the most logical point at which to block passage to enemy submarines. If this be successfully done, it also will fortify other effort having in view the denial of the Channel as an operating ground.

Efforts to block Dover have been vigorously prosecuted for two years and are greatly hampered by strong currents, smooth bottom, heavy seas, great rise and fall of tide, and comparatively great depths of water. While present prospects for successful blocking at a comparatively early date appear good, the great importance of denying passage through the Channel to enemy submarines renders it imperative that we augment the present effort at Dover by other means, if practicable.

In considering mine barrages to the eastward of Dover, we prefer to go far enough east to insure weak currents; but we are limited by the necessity of having the line near enough to receive proper surface support against raids. The line Harwich-Dunkerque is as advanced as we can well protect. Here currents reach 2.3 to 4 knots occasionally, the rise and fall of the tide is between 10 and 20 feet, the hold-


ing ground is good. and depths of water moderate. It will suffice to mine only between Kentish Knock and Dunkerque, through a distance of about 40 miles, with an average depth of 20 fathoms; 12,000 American or destructor mines would give theoretical immunity against surface or submerged passage. This barrage would afford some protection against raids to the Dover patrol forces.

West of Dover the first position which offers any considerable advantage over the practical difficulties encountered in the Straits is the line Hastings-Touquet Point, 37 miles long, and requiring 10,000 American or destructor mines for theoretical immunity against passage. The great amount of shipping passing this vicinity requires that a mine barrage here should be deep. This barrage would be practically immune against surface raids.

The line Isle of Wight-Cape Barfleur has the distinct advantage of permitting a barrage to be laid to the surface if shipping can all be diverted through the Solent. It has the great disadvantage of strong currents, which, at springs, reach 5.4 knots near the French coast and 3 knots throughout the rest of the line. Consequently, this position should not be chosen if it can be avoided.

The last position which we need consider is the line Start Point-Sept Isles, 90 miles long, and requiring 40,000 American or destructor mines for the theoretical immunity against the passage of submarines. It is across currents not exceeding 2 knots, except close to the French coast. The southern half of this line is little frequented by incoming traffic, and therefore surface mines would not present much danger to shipping; the northern half, however, could be a deep mine field only.

The necessity for making this line, as well as all others, at least in large part a deep field, requiring a great patrol force, leads to the conclusion that the Dover area, where lines are shorter, is the best locality in which to deny passage.

In the Dover area the efficiency of the patrol may be increased and its protection facilitated by the installation of a system of ground listening devices operated from shore. To avoid noise interferences due to ordinary traffic (as well as to the movement of loose material on the bottom) such a system would have to be placed about 20 miles to the eastward of the Straits.

We now come to the consideration of the other phase of the Channel question—that of denying the Channel as a theater of operations.

Unless both entrances can be practically closed, there will always exist some probability that submarines will enter from one end or the other to prey upon the large volume of concentrated traffic. We have examined the possibility of closing the western mouth and concluded it to be impracticable, so that, regardless of the efficiency


of our effort at Dover, the enemy will want to operate in the Channel, and will enter from the west if it is unprofitable to pass from the east.

With the means at our disposal it is practically impossible to absolutely deny the Channel to enemy submarines, so that our problem assumes the form of how to render this area so unprofitable a hunting ground as to make the enemy practically abandon it.

Were it not for the ability of a submarine to bottom, and thus destroy sound touch, hunting groups equipped with listening devices could probably make the Channel untenable to the enemy. West of a line Start Point-Sept Isles the depths are generally more than 40 fathoms, and therefore too deep for bottoming. Here listening-hunting groups may be profitably concentrated, whereas farther east such an effort will be somewhat wasted, owing to the prevalence of depths which permit bottoming.

In the eastern section the best means at our disposal appear to be surface patrols in combination with deep mine fields. A force of 30 destroyers or P-boats, 15 on station at a time, day and night, could patrol this area very effectively, and thus instill the constant fear of being hunted into submarine personnel, prevent him from peacefully charging batteries, and generally hamper his Operations. There are now 19 French destroyers assigned to hunting squadrons in their Channel command, which should be available for this duty. A system of ground listening devices, installed in areas free from excessive sound interferences from ordinary traffic, or where in clear daylight good vision is permitted from the shore station, would facilitate putting the patrols in touch with the enemy. Air patrols and kite balloons installed on surface patrol vessels would serve the same purpose.

The patrol effort should he augmented by a series of deep mine fields, so that at every dive submarines will feel that they are running a great risk. It would be necessary to use a type of mine which would become inoperative on breaking adrift, or else, in deep water, a ground mine of destructor type. There are in the Channel large areas of ground so rocky as to render it dangerous for submarines to bottom except with great care. By taking advantage of this fact the requisite number of mines may he reduced greatly. Probably a total of 40,000 would suffice.

It should be noted that with deep mine fields planted on or near traffic lanes the merchant ships will themselves constitute an important element of the patrol, and submerged submarines can attack them only at great risk.

The localities in which deep mine fields should he laid are those most frequented by the enemy. As he selects new areas, they should


be mined, until he is finally driven out, which will come not so much as a result of the small tonnage sunk per submarine in comparison with other areas as on account of the great moral strain on personnel when operating and having to dive frequently in mine-infested area.

Until extensive deep mine fields can be laid, and a ground listening system installed, it will be necessary to assist the patrols by at least a few listening units. During this interregnum one of the principal problems of the operations will be how to deal with a bottomed submarine. The trailing wire and depth charge method will always be a good procedure when the submarine is no longer heard, but it abandons for the time being any possibility of listening, and will probably not give very good results in a tideway against a drifting submarine. An alternative method is to mine in the bottomed submarine. Assuming the bottomed submarine to be within 500 yards, and direction known, the prompt anchoring of a buoy and the planting of deep mines downstream will give good promise of success. Five or six American or destructor mines planted 200 feet apart might be sufficient. Those mines which are not then exploded by the submarines will remain a menace to others forced to dive in that vicinity in the future, thus assisting the general plan of making submerged navigation dangerous.

West of the line Start Point-Sept Isles the general principle already applied to the eastern area, viz, to exclude the enemy from shallow water by the mine, combined with surface patrols, in order to enable more profitable employment of hunters in deeper waters, should govern. The areas from Start Point to Lands End and thence northward off the Cornwall coast should he mined irregularly with deep fields, where the ground is favorable for bottoming, and patrolled. The French coast in this area is bold, rocky, exposed, has strong tidal currents, and consequently requires no special treatment of this nature. Probably 5,000 mines would be necessary for this purpose.

Including barrages in the Dover area and deep mine fields in the Channel, a total of about 70.000 mines will probably be required. In view of the importance of these projects, and the ordinary delays incident to obtaining large numbers of mines, orders for their manufacture should be placed immediately.

Channel convoy system.—With regard to the convoy system in the Channel, comment upon assembling from and convoy to various ports is omitted, because it is assumed—-

(a) That to improve present methods will require more escorting vessels than are available.

(b) That measures advocated above will eventually eliminate the necessity for convoys in the Channel, at least eastward of Cherbourg, or else render escort requirements very light.


Independent of the above questions, we may increase the efficiency of the Channel convoy system by—

(a) Carrying a kite balloon on at least one vessel of the escort.

(b) Placing convoys in a formation of wide front, and reducing its front as the depth of the formation increases: Thus




(c) Adopting the policy of a determined depth-charge attack with several vessels of the escort against every attacking submarine. In time this will make him less willing to approach near a convoy. As this policy is principally an attack upon enemy morale, and since a submarine can not estimate within probably a thousand yards of the distance from her at which a depth charge explodes, the attacking escort vessels should make a liberal use of depth charges, whether or not the position of the enemy is accurately known.

(d) Laying a zone of deep mine fields along the usual routes of traffic. Zones 10 miles wide from Lizard Head to Dungeness and from Portsmouth to Havre will require about 50,000 American mines if spaced at intervals of 500 yards. The application of the method advocated in the discussion of the problem of “denying the Channel as a theater of operations,” by which deep fields were to be laid in the areas most frequented by the enemy, as an adjunct to a system of surface patrols, would finally result in zones of deep mine fields practically coinciding with steamer lanes.

(e) Arranging convoy sailings so as to avoid passage at night during moonlight. This is desirable, owing to the high percentage of sinkings during these conditions.

Note.—Should experiments now in hand demonstrate that the large-mesh torpedo net is of value at convoy speeds, steps should be taken immediately to equip merchant ships with torpedo nets.


1. To unify the Channel command.

2. To man with American crews the present French antisubmarine Channel forces, exclusive of harbor defense craft.

3. When practicable to augment the present antisubmarine effort at Dover by—

(a) A mine barrage (deep and surface) from Kentish Knock to Dunkerque.

(b) A deep mine barrage from Hastings to Touquet Point.

(c) A system of ground listening devices operated from shore, located about 20 miles eastward of Dover Straits.


4. To organize immediately a continuous surface patrol east of line Start Point-Sept Isles, with a total force of 30 destroyers or P-boats, the patrol to be assisted by ground listening devices operated from shore, by air patrols, and by kite balloons.

5. To augment the above patrol by a series of deep mine fields; planting continuously in the usual areas of enemy operation until he abandons the Channel.

6. Until extensive deep mine fields can be laid, to employ a few hunting groups in the eastern Channel in conjunction with the patrols, and to develop tactics for “mining in” a bottomed submarine with deep mines.

7. To concentrate hunting effort west of the line Start Point-Sept Isles: and to assist this effort by deep mine fields and patrols in waters favorable to bottoming, off both Cornwall coasts.

8. To place orders immediately for 70,000 additional mines.

9. To increase the efficiency of the Channel convoy system by the following measures:

(a) Carrying a kite balloon on one ship of each escort.

(b) Placing convoys in a formation of wide front which decreases as the depth increases.

(c) Adopting a policy of determined depth-charge attack by several escorts against every attacking submarine.

(d) Arranging convoy sailings so as to avoid passage at night during moonlight.

A. Remarks of British Admiralty on Memorandum No. 14.

The question of unity of command is a large one, and involves many susceptibilities. Patrol vessels are slow and must therefore be stationed in different areas. Administration and repairs must be a local matter, as also mine sweeping and salvage work. The two points on which unity of command seems practicable are the routing of traffic and the control of the hunting forces. So far as these two points are concerned, the routing of convoys is carried out already under admiralty direction, the coastal traffic only being decentralized in the areas through which it passes. Hunting forces, independent of areas, are already being instituted; and these will be moved as required when ready to act as self-contained forces. There is, no doubt, room for improvement, which may lie in the direction of coordinating the hunting forces as they develop. The question of their command is also being gone into.

It is doubtful if the best way of dealing with the submarine menace is to treat the subject in sections. The problem as a whole is to confine the submarine to as small an area as possible, e. g., to the North Sea. This involves concentration of effort and material at the


Dover and Northern barrages. To choose an area such as the Channel and aim at keeping the submarine out of it involves dispersion of effort, and merely intensifies submarine operations in adjoining areas, such as the entrances to the Channel and the Irish Sea.

To block the Straits of Dover is the first step. This is essential, for. unless passage through it is denied to enemy submarines, neither a northern barrage nor one to the west of the Channel is of any avail.

2. The measures proposed by Memorandum 14 are—

(a) A mine barrage (deep and surface) from Kentish Knock to Dunkerque.

(b) A deep mine barrage from Hastings to Touquet.

(c) A system of ground listening devices about 20 miles eastward of Dover Straits.

(a) This barrage could be passed to westward of Kentish Knock. It is 35 miles between the Shoals, with tides up to 4 knots at times. There would be a considerable “dip” on surface mines laid on this line, and they could hardly be trusted to act against submarines on the surface, except at slack water.

(b) This line does not seem to have any advantage over the Dungeness-Gris Nez, or Folkestone-Gris Nez, and is longer.

Two barrages involve two sets of patrol craft and again dispersion of effort; it is better to have one barrage thickly patrolled than to divide the patrols between two. No barrages are of much avail without light, and probably a barrage of deep mines watched by patrol craft with searchlights continually in use is the only really effective block.

Assuming that a barrage in the Straits of Dover can be rendered effective, it is considered that all efforts not required there should be concentrated on the Northern Barrage to the exclusion of that proposed at the western end of the Channel.

The opinion expressed that the closing of the western mouth of the Channel is impracticable is concurred in. The proposal is to make it unprofitable for submarines to use it by means of deep mine fields, T. B. D’s, or P-boats. It is not possible at present to spare any such vessels. Patrolling the line would therefore have to be undertaken by trawlers with little or no support; and the enemy submarines would have practically no difficulty in avoiding them at night or in bad weather. The effect of withdrawing trawlers for the barrage would be that the enemy submarine would find little to interfere with his passage after passing the barrage.

It is proposed that deep mines should be laid in Lyme Bay and in places on the Cornish coast where the enemy submarines can bottom. Also along the traffic lanes in the Channel. This proposal is concurred in, and might be extended to the Irish Sea. It is a question of priority with present resources.


(c) The installation of listening devices—K. tube or other—to the eastward of Dover is already being dealt with.

3. With reference to proposal No. 8, there appears to be no limit to the number of mines required, but an increase in minelayers is equally important.

4. The convoy proposals (a), (b), (c), and (e) are already in operation. Kite balloons are used when weather permits, where they are available, while airships and aeroplanes or seaplanes are also used to a great extent.


Memorandum No. 15.


4 March, 1918.


(Forwarded to British Admiralty, March 11, 1918.)


[Initiated by the Planning Section. This paper received the warm concurrence of the British Plans Division. Memorandum No. 15 was submitted to the Inter-Allied Naval Council (see papers No. 69, 88, and 129, Council files), which disagreed with the general conclusions of the Planning Section.]


General situation: Germany and Austria have made a peace by secret treaty with the Ukraine, and are lending the Ukraine military assistance against the Bolshevists. Germany is dictating a peace with Russia greatly to her advantage.

Required: Estimate of the situation and decisions as to changes in the grand strategy of the Allies incident to the new conditions in the Black Sea region.



To determine—

(1) Changes that should be made in the grand strategy of the Allies to meet the new conditions in the East.

(2) Changes that should be made in the disposition of allied naval forces.


The special naval forces to be considered are not enemy forces as yet, but potential enemy forces, viz, the Black Sea Fleet of the late Russian Empire, as follows:

2 dreadnoughts.

4 predreadnoughts.

2 light cruisers.

4 auxiliary cruisers.

11 submarines.

27 destroyers.

Political conditions in the Black Sea during the past year have not been favorable to the upkeep of vessels. So that, even should


the enemy get control of all the vessels formerly belonging to Russia and now in the Black Sea, we need not expect any of those vessels to be ready for service before 1 June, 1918. At that date we estimate that—

2 dreadnoughts,

2 light cruisers,

2 auxiliary cruisers,

4 submarines,

16 destroyers

might be ready for a limited service, and that other vessels might be ready in the course of time. The forces above enumerated are all the naval forces available to influence a redistribution of allied naval forces to the Dardanelles area. Any redistribution of allied naval forces to the Dardanelles area not designed solely as a containing force for any possible accretions to the force based on Constantinople will come from an altered intention of the Allies.

Peace with the Ukraine was accompanied by a secret treaty with the Ukraine. We do not know the terms of peace. Secrecy may be concerning—

(а) A transfer of naval vessels.

(b) The control of the country during the present war to guarantee crops and their safe transport to Germany and Austria.

(c) Commercial relations.

(d) Restrictions regarding intercourse with the Allies and with other parts of Russia during the continuance of the peace.

(e) Black Sea naval base.

(f) Postwar conditions.

We may be certain that Germany has sought to secure for herself every possible military and commercial advantage, as well as benevolent neutrality of a pronounced type. She thus secures—

(a) The release of her prisoners of war.

(b) The safety of her eastern front.

(c) A new and vast source of food supply—probably available in important quantities after August, 1918.

Note.—If food shortage is thus relieved, Allies will have lost advantages of food blockades—one of their most powerful weapons. Most of the grain from the Ukraine must be transported by water to the Central Powers, as rail transportation is inadequate and rail equipment in poor condition. Allied naval control of Black Sea would deflect all water-borne commerce away from the Central Powers.

(d) A possible addition to her Constantinople naval force.

(e) The release of many army divisions for transfer to other fronts.

(f) The practical security of Turkey from Russian attack.



We have reason to believe that Turkey is dissatisfied with her present alliance and is war weary. Turkish character and temperament do not harmonize with the German. The Turk came into the war primarily to protect himself against Russian aggression; and now that that danger is eliminated he does not relish the inevitable German domination which will follow a German victory. Turkey sees large sections of her richest territory in allied hands.

It is possible that Turkey would welcome a separate peace with us.


At present we are holding the Saloniki-Valona line. This immobilizes a portion of the Bulgarian Army and other enemy troops. Our forces are in Mesopotamia. Their presence there can have no influence on the outcome of this war, unless their achievement is used to induce Turkey to a peace.

Our forces are in Palestine. Their value there is due to the protection they give to the Suez Canal. They will have no other influence on the outcome of this war, unless their achievements are used to induce Turkey to a peace.

We have to decide if a peace with Turkey would be more to our advantage now or later. It is well known that we can not increase greatly our efforts in either Palestine, Mesopotamia, or Saloniki without such an obligation of additional tonnage as greatly to decrease the possible efforts of America in France; in other words, without insecurity in the west. We are now as far advanced in Turkey as at any time during the war.

A peace with Turkey now enables us to use such a peace as a great political and moral lever. Later, if events do not mend, even this lever may be too weak; we are certain it will never be stronger. The advantages to be gained are—

(a) Release of shipping to other employments from Mesopotamia and from Egypt.

(b) Release of military forces from those fronts to other employments.

(c) Denial of Turkish waters to German submarines—especially valuable if Adriatic is denied them.

(d) Opening of Dardanelles to commercial traffic.

(e) Release of about 200,000 gross tons of shipping now shut in the Black Sea.

(f) Possible diversion of Black Sea wheat to Mediterranean markets, and consequent saving in tonnage due to short hauls.


(g) Great moral advantage of detaching a support of the Central Powers.

(h) Naval command of the Black Sea.

Note.—The privilege of passing our naval vessels into the Black Sea should be insisted upon as one of the peace terms.

The disadvantages of a peace with Turkey are all to be found in “ the cost of the peace. ”


From the above we conclude that the eastern situation as well as the course of the war as a whole, demands that—

(1) We conclude a peace with Turkey.

(2) The terms of the peace shall counteract, so far as possible, the advantages of the enemy’s peace with the Ukraine.

Note.—We have in a previous paper, “Memorandum No. 11,” recommended such a peace on other grounds.

As to Saloniki, we recommend that all ports now held continue to be held, to prevent (hem from becoming bases of submarine operations.

Allied naval forces now in the Mediterranean may be redistributed by the commander in chief as occasion requires, in order to contain any accretions to enemy forces based on Constantinople.


Memorandum No. 16.


7 March, 1918.


The British and American Planning Sections are in agreement on the essential features of the Adriatic project. These are—

(a) The seizure of a base at Sabbioncello.

(b) The laying of a mine barrage, Gorgona-Curzola.

(c) The denial of Cattaro to enemy submarines.

Owing to the large number of people who have access to the minutes of the Allied Naval Council, it is considered undesirable that any detailed plans should be submitted to that body.

The agreement of the council should be obtained at the coming meeting of the council:

(a) Agreement to undertake the general features of the plan as above indicated.

(b) Agreement on nationality of Commander in Chief.

(c) Agreement on resources to be supplied by each nation.

(d) Agreement by each nation to appoint an officer who will serve under the Commander in Chief as the representative of that nation.

The resources that will be required of each nation are, roughly:


Naval forces in Adriatic.


Mine layers.

Use of ports as bases.


Naval forces in or near Adriatic.


Troops and transports.

Light cruisers.


Harbor defense nets.






Mine layers.

Troops and transports.

The detailed plans of operations should he decided upon by the Commander in Chief appointed to carry out the operation.

It is well to bear in mind the extreme importance of planning the operation on an adequate scale with regard to forces. It may be necessary to make some radical reductions in the number of naval units at present assigned to other theaters of war; but the great number of forces that will be released in the Mediterranean if the operation is successful may be the deciding factor of the war.

The forces employed should be seasoned forces, speaking the same language. American marines or British Mediterranean troops, or both, are suggested.

As the operations after seizing the base will include a vigorous offensive patrol of the Adriatic to prevent the movement of enemy surface craft, the vessels for this duty should be in adequate force.

The Planning Section is constrained to believe that, unless the Allies are able to inaugurate offensive operations in contradistinction to purely defensive operations, the outlook as to our success in this war is extremely dubious.


Forwarding comment by the Force Commander follows:

“In this connection please refer to my letter No. CS-13279 of April 5, 1918 with which was forwarded Allied Naval Council Paper No. 81 on this subject. Attention is also invited to my cablegram No. 6077 of April 5, which gives the latest information concerning this matter.”



Memorandum No. 17.



12 March, 1918.



(See Maps Nos. 1, 2, and 6.)

General situation: As at present. British vessels have begun laying the Northern Barrage. American vessels will not begin before April.

Special situation: The British and American Planning Divisions decide to review the present and future mining policy, with particular regard to the Northern Barrage.

Required: Estimate of the situation and decisions covering—

(a) Advisability of retarding the laying of the barrage.

(b) Details of any mining plans proposed as a substitute for, or in addition to, the Northern Barrage plan.



To determine present and future mining policy with particular regard to Northern Barrage.


The general situation is such that continuance of present rate of tonnage losses can not be permitted without ultimate defeat. The next six months will present the gravest tonnage difficulties.

Time is an important factor; a submarine locked in or put down now is worth three submarines treated similarly six months from now.

The proved efficiency of the submarine mine as a defensive weapon against the submarine renders it imperative that we utilize this weapon to the maximum possible extent.


While the supply of mines at present is limited, we are in a position to produce them rapidly in large numbers from this time forth.

The question really at issue is, What is the best possible use of our present available mining resources?

Our special and immediate naval mission in this war is to obtain subsurface command of the sea, while still retaining command of the surface of the sea. The character of our mining operations is dependent on this mission.

If, instead of scattering our mining effort over the whole theater of operations, we concentrate upon containing the enemy, we at once keep our expenditure of material and our operating effort within reasonable bounds; while at the same time we derive the maximum benefit from each mine planted.

Experience has demonstrated the necessity of locating mine fields sufficiently near our own bases to insure proper support both to the mines and to the patrols.

We therefore conclude our basic mining policy to be—

“To concentrate mining effort upon containing enemy submarines, locating barrages sufficiently near our bases to insure adequate support to mines and to patrols.”

Obviously the exits from the most important bases need blocking first. Present plans to barrage Dover and Scotland-Norway are therefore sound. In view of the shorter distance to the operating ground offered by the Dover route to the enemy, we conclude—

“First to make the Dover passage unprofitable to the enemy.”

We suggest the desirability of a surface barrage from Kentish Knock to the vicinity of Dunkerque, and of a deep barrage from Hastings to Touquet Point, as desirable measures additional to the present effort at Dover.


The present plans for the Northern Barrage have been discussed in previous papers. The net result of collaboration of the British and American authorities has been—

(a) The joint decision to lay the Northern Barrage.

(b) The British decision to stop the barrage outside neutral waters.

(c) The British decision to support the patrol of the barrage from home waters—this decision being necessary because of political considerations.

(d) The British decision to adhere to the open-ended barrage until its efficiency is demonstrated by experience.


The efficiency of the open-ended barrage depends on the efficiency of patrol support as a means of keeping submarines submerged beyond 40 feet. The waters that must be patroled are:

Deep mine field. Area B 50
Open water, Area B 15
Deep mine field, Area C 50
Norwegian waters, Area C 30
Total patrol line 145

Assume most favorable conditions, viz:

(а) Good weather.

(b) Good visibility.

(c) No breakdowns of trawlers.

(d) Listening equipment good for 2 miles.

(e) Speed of trawlers, 10 knots.

(f) Stay at sea 8 days.

(g) Stay in port 8 days.

(h) Perfect position keeping is possible.

Average distance of Area C trawlers from base is 160
Average distance of Area B trawlers from base is 35
  Allow one trawler on station every 4 miles:  
  Trawlers required on station will be—  
  Area B 16
Area C 20
Total trawlers required for—  
  Area B 32
Area C 52
Total 84

If, instead of the most favorable operating conditions and the greatest possible efficiency of units, we assume excellent average conditions, not less than double the above number of trawlers will be required to maintain a semblance of efficient patrol, which exceeds the number available.

In bad weather the patrol will offer no opposition to the passage of submarines; witness recent efforts in Fair Island passage, whose trawlers were driven off by bad weather repeatedly, and thus allowed submarines to pass whose approximate time of arrival was known.

Bad weather will scatter patrol forces, with all the consequent damage to vessels, vessels’ equipment, and to personnel. The usual practice now is to send trawlers in every four days for provisions; for trawlers to seek shelter in bad weather; and for the trawlers to stay out a total of eight days per trip. In spite of these comparatively mild operating conditions, trawler service is very strenuous. It is now proposed to make the service in Area C at least twice as strenuous as heretofore and to expect efficiency. There will be no


efficiency in rough weather, nor for a day or two after bad or thick weather.

Trawlers are not accustomed to deep-sea navigation, so that position keeping is going to be bad. Thick weather will invariably favor the submarine.

From these considerations we conclude that Area C (if deep mined only) will never present any real deterrent to the passage of enemy submarines. Those that pass to the eastward of Area A, however, will have to travel about 90 to 120 miles farther to reach the Atlantic than they travel at present when using the Fair Island passage. Were Area C mined to the surface and up to the territorial waters of Norway, enemy submarines would (if they avoided the barrage by passing through Norwegian waters) travel 120 to 150 miles farther to reach the Atlantic. Either of these detours means only the loss of one operating day per trip—a loss not sufficient to justify so great an effort on our part as the laying of the barrage.

The difficulties of the patrol of Area B and of the open water to the westward are far less than the difficulties in Area C, and more like the well-known difficulties at Dover, minus raids.

Assuming that the enemy will know of the clear water west of Area B, we see no great difficulty for him in gaining the Atlantic by this route, thereby avoiding the loss of a day in making the eastern detour.

It is obvious that if State policy or other considerations require gaps at each end of the line, such gaps must be greatly reduced. We believe that the eastern gap should not exceed 3 miles in length and the western 20 miles.

We must recognize the ultimate necessity of closing these gaps altogether, and must so draw our original plans as to cause ourselves no unnecessary inconvenience or delay in taking these final steps when necessity arises.

The effectiveness of the barrage will eventually require a Norwegian base. While we will not need the services of the base until patrol of Area B is begun, it is highly desirable that the enemy be prevented from securing for himself the base which we desire. We should at once seize the base; or, if State policy does not permit this step at present, we must be prepared to drive the enemy out very promptly should he forestall us.

In view of the probable completion of the barrage in the autumn if pushed to completion continuously, we should consider the alternative of postponing the laying operations so as to finish next spring, when patrolling can be more efficiently conducted. Reasons which favor postponement are:

(a) Winter weather, which will damage the barrage and require renewals.


(b) Difficulty of winter patrolling and consequent relative inefficiency of the barrage during bad weather and long nights.

(c) Pressing need for mining elsewhere in northern waters.

Reasons against postponement are—

(a) A concentration on this project to the exclusion of others in northern waters may expedite its final completion so as to have it effective in the late summer.

(b) The barrage will be partially effective at all stages of completion.

(c) The sooner we approach to the fundamental principle of preventing egress from enemy bases the greater will be our freedom and flexibility of action in undertaking offensive antisubmarine, measures.

(d) Deep mines can be but very little affected by winter weather, and they constitute the major portion of the barrage.

(e) A shipping crisis may arise requiring the virtual or partial abandonment of the convoy system in order to reduce the loss of efficiency in freight carriage which the system entails. If, then, we have the Northern Barrage completed, or even completed in the deep fields only, we are in a position to effectively vary our antisubmarine strategy and concentrate several hundred destroyers and many more trawlers, etc., in the North Sea.

(f) The barrage must not he considered as an undertaking which will ever be complete while the war lasts. It is a project requiring almost continuous mining. The greater the number of mines laid the more effective it will be. The project is such a great one that wisdom requires us not to delay in reaching even partial efficiency.

(g) American mines whose upper antennae become destroyed by wave action are still effective as deep mines.

With respect to the Northern Barrage, we therefore deduce our policies to be—

1. To concentrate upon vigorous mine-laying measures to the exclusion of other northern theaters except Dover.

2. To modify original plans so as to cause ourselves no unnecessary inconvenience in the final stages of closing gaps.

3. To seize a Norwegian base: or, if State policy forbids this at present, to be prepared to drive out the enemy promptly should he seize such a base.

4. To abandon the Northern Barrage unless its design is corrected.


The area next in importance after the North Sea is the Mediterranean, where the enemy has bases in the Adriatic and inside the Dardanelles. The shipping losses by enemy action in this area amount to 30 per cent of the total.


Recent political events may result in the enemy becoming a Black Sea naval power. It is important, therefore, that the Dardanelles exit be mined.

Plans now under consideration contemplate an allied naval offensive in the Adriatic, which includes “mining-in” Adriatic bases. Should such a decision be reached it will be possible to undertake some mining there without interfering with the effort at Dover or in the North Sea. It may possibly require a slight retardation of the Northern Barrage to insure the early completion of the Adriatic Barrage.

Sound strategy requires a concentration of our strength at points of enemy weakness. We will be justified in somewhat retarding the Northern Barrage if, by so doing, the Mediterranean situation can be adequately dealt with promptly. In this case the general strategic principles are fortified by the promise of an early release of large antisubmarine forces for employment in the north, as well as by partially relieving the acute shipping situation through the abandonment of convoy operations in the Mediterranean.

We therefore conclude our policy to be:

A. When decision is reached for an Adriatic offensive to lay a barrage there, retarding the Northern Barrage if necessary.

B. To “mine-in” the Dardanelles entrance.


Until the foregoing primary policies are completed, we can not afford to engage in any secondary mining operations which will interfere with them. To do so will mean long continued inefficiency of our measures as a whole. The interval of comparative inefficiency must be made as short as possible, which necessitates concentration of present effort upon primary needs.

The only justification of a departure from these principles will be a crisis of a nature which will not permit sufficient time to complete the major projects. Such a crisis is not to be expected before autumn, which coincides with the approximate date of completion of the largest project—the Northern Barrage—if it be pushed vigorously to completion.

Auxiliary operations in support of the major projects should receive first consideration.

The mining in of the Helgoland Bight and the Kattegat accords with our general mining policy of containing the enemy; but we can not rely upon the efficiency of such operations. During the winter we have had considerable success in the Bight with the ordinary type of mine. A nonsweepable type will be essential to equal success during the summer. In the Kattegat, unless we are prepared


to undertake a major operation, and to violate the neutrality of Sweden, Denmark, and Norway, we can not have an efficient barrage. The best auxiliary effort we can make is a deep barrage combined with a patrol of submarines.

The second form of auxiliary effort to be considered is the defense of shipping. For this work the mine is especially useful in coastal waters where traffic becomes concentrated, and in waters less than 40 fathoms deep where hunting is difficult owing to the ability of the submarine to bottom.

As the Dover and Northern Barrages become effective, we must expect increased enemy activity on the east coast trade of Great Britain. Here water is less than 40 fathoms, so that the mine may be used profitably in conjunction with other forms of defense. This area requires special study.

Similarly the Irish Sea and English Channel require separate treatment.


1. To concentrate mining effort upon containing enemy submarines, locating barrage sufficiently near our bases to insure adequate support to mines and to patrols.

2. First to make the Dover Passage unprofitable to the enemy.


1. To concentrate upon vigorous laying of the Northern Barrage to the exclusion of other northern theaters except Dover.

2. To modify original plan so as to cause ourselves no unnecessary inconvenience in the final stages of closing gaps.

3. To seize a Norwegian base; or, if State policy forbids this at present, to be prepared to drive out the enemy promptly should he seize such a base.

4. To abandon the Northern Barrage unless its design is corrected.


1. When decision is reached for an Adriatic offensive to lay a barrage there, retarding the Northern Barrage if necessary.

2. To mine in the Dardanelles entrance.


1. To refrain from auxiliary mining except such as will not interfere with the main projects, and except in the event of a crisis of nature which will not permit sufficient time to complete the major projects.


2. To give special study to the question of the protection of merchant vessels by mining operations on the east coast of Great Britain, in the English Channel, and the Irish Sea.


[Joint estimate of the situation by the British and American Planning Divisions. 18 March, 1918.]

General situation: As at present. British vessels have begun laying the Northern Barrage. American vessels will not begin before May.

Special situation: The British and American Planning Divisions decide to review the present and future mining policy, with particular regard to the Northern Barrage.

Required: Estimate of the situation, and decisions covering—

(a) Advisability of retarding or modifying the laying of the barrage.

(b) Details of any mining plans proposed as a substitute for, or in addition to, the Northern Barrage plan.


To determine present and future mining policy, with particular regard to Northern Barrage.


1. The Northern Barrage can not he completed before the autumn. One system should be completed by about July 1.

2. It is of vital importance to keep down our tonnage losses this summer. The measures taken must, therefore, be such that they become effective to some degree at once, and improve as they approach completion.

3. The object in view is to decide what is the best use to make of the resources available for mining operations.

4. If we vigorously oppose the enemy’s submarines with mines and patrol craft, he will attempt to remove the obstacle by strong raiding attacks. The mine fields must, therefore, he placed so as to obtain the utmost concentration of our patrol forces in positions from which the enemy can not drive them.

5. We therefore conclude that our present policy of concentrating our main mining effort on confining the submarine to the North Sea and locating the barrages in the Norway-Orkney and Dover areas is sound and should be continued.

6. Although alternative proposals to block the Helgoland Bight and Kattegat by intensive mining have been examined (vide P. D. 054) and rejected, this policy may eventually become necessary, and


with this end in view it is strongly recommended that a large reserve of mines should be accumulated, the British and United States of America mine-laying capacity increased, and that the Allies should quickly make themselves independent of Swedish supplies.


7. It is assumed that the present plans for the Northern Barrage are known.

8. It will not be complete during the summer months of 1918, when the best value can be got out of our patrol craft.

9. It may be, therefore, all the more important to obtain the maximum concentration of patrol craft in these waters as early as possible.

Further study to this subject should be given by the British and American Planning Sections as soon as possible.

9a. It is considered that the sequence of laying the deep mine field in Area B (western section) should be so arranged as to obstruct the normal approach of submarines to the Fair Island Channel as early as possible. It is understood that this is being arranged.

10. The following previous decisions appear to require examination:

(a) The decision to stop the barrage outside neutral waters.

(b) The decision to support the patrol of the barrage from home waters, thus abandoning the idea of a Norwegian base.

(c) The decision to adhere to the open-ended barrage only until experience shows that it can not be effectively patrolled.

11. To economize patrols in Area B provision should be made to extend the surface mine field west from Area A as soon as our resources admit, so as to reduce the width of the western gap to not more than 20 miles.

12. Area C—the portion next the Norwegian coast—is difficult, to patrol without a base on that coast. With the present arrangements for patrolling Area C, the work will be at least twice as strenuous as any hitherto demanded of the trawler service.

13. It is therefore considered that if Area C is deep mined only it will never present any real deterrent to submarines.

14. The efficiency of Area C would be increased by laying a surface mine field also and reducing the gap at the Norwegian end of the barrage to the 3 miles of territorial water.

15. If Area C is closed as above, and proclaimed, submarines can avoid it by using Norwegian territorial waters, and unless it is decided to attack them in neutral waters, this gigantic mining effort will he rendered useless,

16. Norway can hardly be expected to resist the passage by German submarines; and should the situation arise, it would be neces-


sary to exercise a control over Norwegian territorial waters or to seize a Norwegian base.

17. The course of action which would best overcome all the difficulties detailed in paragraphs 12 to 16 would be to seize, at the earliest possible moment, a base in Norwegian waters. This subject has been investigated more fully in P. D. 049.

18. It must be recognized that the establishment of such a base is necessary to render the Norwegian barrage complete, and it is for the government of the day to decide whether the great naval advantages which would follow from this course of action would justify the infringement of Norwegian neutrality.

19. It is assumed that if this is decided in the negative we shall still be prepared to attack enemy submarines in Norwegian territorial waters; otherwise the laying of the barrage would be a gigantic waste of effort, and should be abandoned forthwith.

20. As the Northern Barrage can not be completed before autumn, it has been suggested that the laying operations should be postponed so as to finish next spring, when patrolling once again becomes effective.

21. Reasons which favor the postponement are:

(a) Difficulty of winter patrolling, and consequent inefficiency of the barrage during bad weather and long nights.

(b) Wastage of barrage and patrols may be out of proportion to the results obtained.

(c) Possibility of using the mines more effectively elsewhere.

22. Reasons against postponement are:

(a) The barrage will be particularly effective at all stages of completion; and the need for dealing with submarines at once is pressing.

(b) The deep mines, constituting the greater part of the barrage, will be little affected by next winter’s weather. American mines whose upper antennae are destroyed by wave action are still effective as deep mines.

(c) If a shipping crisis arises, requiring the virtual or partial abandonment of the convoy system in favour of the blocking of the North Sea, exists, the existence of part of the Northern Barrage will economize patrols.


23. It is considered that our policy should be—

(a) To concentrate our main mine-laying resources upon the Northern Barrage and Dover.

(b) To arrange the sequence of laying deep mines in Area B, so as to cover the approach to the Fair Island Channel as soon as possible. It is understood that arrangements have already been made to do this.


(c) To provide for the ultimate extension of the surface mine field, over Area C to Norwegian territorial waters and part of Area B.

(d) To be prepared to patrol Norwegian territorial waters, or to seize a base in Norway, so as to facilitate the patrol of Area C: or. if State policy forbids the latter course, to be prepared to eject the enemy promptly should he seize such a base.

24. It is almost certain that the Northern Barrage, as at present designed, will not fulfill its purpose; and great importance is attached to the above recommendations.

25. In view of the coordination required between the mine laying, the patrols, and the Grand Fleet, the whole of the operations should be conducted by commander in chief, Grand Fleet, and all the necessary vessels should be under his command. It is understood that the admiral now commanding the Northern Barrage patrol is acting under the commander in chief’s orders.

26. Similarly, the whole of the operations in the Narrow Seas, including the blocking of the Dover Straits, should be under one command.


27. The shipping losses by enemy action in the Mediterranean are 30 per cent of the total. This area, therefore, is second to the North Sea in importance.

28. The enemy has bases in the Adriatic and inside the Dardanelles; and extension of his resources within the Dardanelles exit in the future is by no means improbable.

29. Plans now under consideration contemplate an allied naval offensive in the Adriatic, which includes mining-in Adriatic bases. Vide American Problem No. 5. Steps should be taken now to provide any additional facilities required.


It would be bad policy to undertake any auxiliary mine-laying operations which did not assist—or, at any rate, tended to interfere with—the execution of the main operations already discussed.

The only justification for departure from this principle would be the anticipation of a crisis of such a nature that the major operations could not be finished in time to effect our object.

The mining of the Helgoland Bight has had considerable success; but reliance can not be placed on the efficiency of such operations in future, especially during the summer when sweeping is easier.

For the defense of shipping the mine is useful in coastal waters, where traffic becomes concentrated, and in water of less than 40 fathoms, where hunting is difficult, owing to the ability of the submarine to lie on the bottom.


Auxiliary mining operations of this description, in conjunction with other forms of defense, are likely to be profitable on the east coast of Great Britain, in the English Channel, and in the Irish Sea. Each of these areas requires separate study and treatment. If these operations released patrol craft for Dover or for the Northern Barrage they would directly assist the main projects.


It is considered that our general policy should be—

(a) To concentrate our main mine-laying resources upon the Northern Barrage and Dover.

(b) To modify the Northern Barrage in accordance with the suggestions in paragraph 23.

(c) Until Dover is complete and the Northern Barrage well advanced, to undertake no other extensive mine-laying operations which might interfere with these projects.

(d) To be prepared to undertake rapidly an operation on the Norwegian coast, should the political situation give an opening for it, or should Germany take the initiative.

(e) To give further study to the question of concentrating as early as possible, a proportion of the auxiliary patrol trawlers and escort destroyers in the northern area, and placing the whole of the operations in these waters under the control of the commander in chief, Grand Fleet.

(f) To undertake mining operations in the Adriatic and at the Dardanelles, and to provide any additional facilities required.

(g) To refrain from auxiliary mining, except such as will not seriously interfere with the main projects.

(h) To give special study to the protection of merchant vessels, and the economizing of patrol vessels by mining operations on the east coast of Great Britain, in the English Channel, and in the Irish Sea.

(i) To increase British and American mine-laying capacity, and to accumulate a large reserve of mines.


[As prepared by Plans Division, British Admiralty. March 15, 1918.]

Particular attention is drawn to paragraph (d) in the summary of contents and paragraphs 17 and 18.

Very extensive and continuous mining operations in the Kattegat and Helgoland Bight may eventually prove necessary as a last resource for dealing with the submarine menace during the winter.

In order that we may be prepared to carry out the policy a large reserve of mines should be accumulated, the present mine-laying


capacity increased, and the Government urged to make definite arrangements for rendering the Allies independent of Swedish supplies.

Summary of Contents.

This paper examines the question of mining the Kattegat and comes to the following conclusions:

(a) The comparatively small delay which a deep and shallow mine field completely blocking the Kattegat might exercise on the enemy’s submarines would not repay the extreme probability of Swedish and Danish hostility, and this course of action is not recommended at present.

(b) If a clear channel were left on both sides of mine field for the passage of neutral shipping through territorial waters, the neutrality of Sweden and Denmark would probably be maintained, but there would be great difficulty in supporting the mine field and preventing the passage of submarines through territorial waters. Although the laying of such a mine field is examined in Appendix II, it is not recommended.

(c) Mining operations in the Kattegat should for the present be confined to deep mine fields, watched by submarines and occasionally patrolled by surface craft as recommended in P. D. 041 or 20/1/18.

(d) Mine laying on a very large scale, commencing in the vicinity of the Sound and Belts, in conjunction with similar operations in the Helgoland Bight, may eventually become necessary as a last resource. In anticipation of this the British and American Navies should increase their mine-laying capacity and the Allies should make themselves independent of Swedish supplies.

Appendix I deals with the economic effect of Swedish and Danish hostility.

Appendix II examines in detail the laying of a combined deep and shallow mine field in the Kattegat, on the assumption that a clear passage must be left for neutral shipping.

[Reference: Chart No. 2114.]

1. It has been suggested that the idea of the Northern Barrage should be modified in favor of deep and shallow mine fields in the Kattegat and Helgoland Bight.

2. The main spheres of mining effort are at present—

(a) The Northern Barrage.

(b) Dover.

(c) The Helgoland Bight.

3. The mining policy with regard to (b) and (c) does not appear to be questioned, and the matter resolves itself into the possibility


of mining the Kattegat, with consequent modifications in the plans or time-table of the Northern Barrage.

4. An operational distinction must be drawn between patrolled and unpatrolled mine fields, for the latter can never be a permanent obstacle. The comparative success of those in the Bight are due to special circumstances, and the fact that the enemy prefers the line of least resistance through the Kattegat.

5. The possibility of mining the Kattegat has been carefully considered on various occasions, and in January, 1918, it was suggested that a deep mine field should be laid on the east side of Laeso Island, between Kobber Grund Light and Malo Island, with occasional surface craft patrols as an essential part of the operation (vide P. D. 041 of 20/1/18).

6. If this plan had been carried out submarines entering or leaving the Kattegat submerged would have had to pass through mined areas and these would have been temporarily controlled by destroyer forces supported by the Grand Fleet during periods of special submarine activity.

7. A shallow mine field right across the Kattegat would for all practical purposes shut off Sweden and Denmark from the outside world. It would exercise the severest pressure on Sweden, and besides making her entirely dependent on Germany, would deprive the Allies of certain important supplies (vide Appendix I).

8. The risk of Sweden and Denmark joining Germany should, however, be accepted, and no question of international law should be allowed to stand in the way if the suggested mine field were likely to limit to any great extent the enemy’s submarine activities.

9. Once, however, the passage of submarines was seriously threatened, the enemy would strike at the points of resistance, and unless we are prepared to fight the enemy fleet simultaneously in the Bight and Kattegat, the permanent blocking of these areas does not appear to be practicable (vide Appreciation on blocking the German rivers and Baltic, prepared by the Planning Section in August, 1917).

10. Also if the Kattegat were completely blocked by mines, it is almost certain that the Danes and Swedes would join Germany in assisting to clear a passage up the coast, and the sweeping operations would be supported by the High Seas Fleet from convenient Swedish anchorages such as Marstrand Fiord.

11. The conclusion is that the comparatively small delay which such a mine field might possibly exercise on the enemy’s submarines would not repay the extreme probability of Swedish and Danish hostility.

12. If, however, a deep and shallow mine field (for details of mine field vide Appendix II) were laid in the area lying between the Skaw and the Patternoster Rock, and particular care were taken to leave


a clear passage for neutral trade through Danish and Swedish territorial waters, these countries would not be seriously affected, and their neutrality would probably be maintained.

13. But the dangerous areas would have to be notified and there is little doubt that neither the Swedes nor Danes would seriously dispute the passage of enemy submarines through their territorial waters. The efficiency of such a mine field would, therefore, depend on our ability to prevent sweeping operations and the use of territorial waters by enemy submarines.

14. No reliance should be placed upon our submarines for exercising this control, and the most we could do in that direction would be an occasional patrol by destroyers supported by the Grand Fleet. The mine field would also require about 4,000 mines, thus delaying the Northern Barrage by about three weeks.

15. Although a plan (vide Appendix II) for a combined surface and deep mine field in the Kattegat has been worked, out, it is not recommended for adoption.

16. It is considered that mining operations in the Kattegat should for the present be confined to deep mine fields occasionally patrolled by surface craft (vide P. D. 041 of 20/1/18) and that during the forthcoming summer we should concentrate our patrol and mining efforts on the areas where they can be supported.

17. Although the blockade by shallow mines of the Kattegat is not recommended at the present time, it may eventually be found necessary as a last resource, especially during the winter months when sweeping operations in the Helgoland Bight are difficult.

18. For such a campaign to have any considerable delaying action on the submarine campaign it would have to be carried out on an exceptionally large scale and operations would have to commence well to the southward in the vicinity of the Sound and Belts. It would first be necessary to increase the British and American minelaying capacity, and the Allies would have to make themselves independent of Swedish supplies.

Appendix I.

1. The situation, if all sea-borne traffic via the Skagerrack and Kattegat were cut off from Sweden and Denmark, requires to be examined under four headings:

(1) The effect on Sweden.

(2) The effect on the Allies as regards Sweden.

(3) The effect on Denmark.

(4) The effect on the Allies as regards Denmark.

The following authorities have been consulted: Trade Division, War Trade Int. Department, M. I. 6 B., Iron and Steel Production


Department (of Munitions Supply Department), Director of Ball Bearings (of Small Tools Department), and Explosives Supply Department.


(a) Sweden would practically starve.1 At the best she would be reduced to the same condition as Germany, provided she placed herself unreservedly in Germany’s hands and invoked her economic assistance. In short, she would be driven into Germany’s arms.

(b) As regards coal, however, Sweden depends on our supplies2 to enable her to eke out her requirements; as it is, wood is being largely used on the railways. Germany would not be able to make good the loss of our coal exports to Sweden, owing to her impaired railway facilities.

Note.—Access to the ports of Stromstak, Uddevalla, and Gothenburg would probably permit of sufficient supplies reaching Sweden to keep her from actual starvation. But there is little doubt that the indignation and feeling aroused would very seriously prejudice important supplies of ball hearings and carbide and would shatter any chance of effecting an arrangement for limiting Swedish exports of ore to Germany. (See par. 3.) Indeed the probability is that Sweden would join the Central Powers.


(a) One-third of our requirements of ball bearings is supplied by Sweden. We have recently had to offer her inducement to increase her output in order to enable us to cope with aircraft, tank, and other construction. Our own output is increasing, but in the most favorable circumstances we should not be self-supporting in respect of bearings for at least four months, and then only if our requirements had not materially increased in the meantime. The Small Tools Department of the Ministry of Munitions consider that deprivation of Swedish ball bearings at the present juncture would be in the nature of a disaster.

(b) With regard to Swedish iron ore, we have a year’s requirements waiting shipment at Narvik. The Foreign Office, however, attach, great importance to bringing off a contract with Sweden for 2,450,000 tons of ore. This would reduce the amount exportable to Germany from 5 million to 3 1/2 million tons per annum—an amount which is considered inadequate for Germany’s needs and which will result in disorganization and an increased demand for fuel and labor combined with a diminished output. The Foreign Office attach great importance to the completing of this contract as a measure calculated to hinder gravely Germany’s conduct of the war. They do not


1 Sweden imported 120,000 tons of corn and grain and 45,000 tons of fodder daring 1917 from overseas.

2 We supplied 700,000 tons of coal and coke during 1917.


credit Dutch reports as to the large reserves of Swedish ore held by Germany.

(c) By the terms of an agreement which it is expected will be ratified shortly, the Allies will obtain practically the bulk of Swedish shipping.

(d) France depends on the Norsk Hydro for ammonium nitrate.1 The Norsk Hydro produces this synthetic nitrate from cyanamide, the great bulk of which is provided by the North Western Cyanamide Co. of Norway. In its turn the cyanamide is formed from calcium carbide, obtainable only from the Alby Carbide Co. of Sweden.


(a) Denmark depends on our exports of coal to eke out her requirements. It is not considered that Germany could make good the deficit2 consequent on our stoppage of export.

(b) Denmark would certainly be driven commercially into the arms of Germany, although she would have sufficient food for her own requirements.

(c) By an agreement which it is expected will shortly be ratified we shall obtain a large proportion of Danish shipping in return for supplies on what is considered a satisfactory rationed basis.


Danish exports of food to the United Kingdom are convenient but not essential.

Appendix II.


[References: Charts Nos. 2114 and 129, Tides and Tidal Streams, 1909, p. 158; North Sea Pilot, Part IV, p. 308 (Skaw); Norway Pilot, Part I, pp. 412-424 (Swedish coast).]

1. Owing to the delay in the completion of the Northern Barrage, the possibility of interim schemes requires consideration.

2. The object in view is to produce the maximum interference possible with the passage of submarines through the Kattegat, while leaving a free passage open to neutral shipping.

3. Two proposals have been considered:

I. Mine fields on either side of Laeso Island (57° 16' N., 11° 0' E.), the eastern one running to Tistlarne (57° 31' N., 11° 44' E.)

II. A mine field from the Skaw to the Paternoster Rocks (57° 54' N., 11° 30' E.), on the Swedish side.


1 In a note (dated 10/12/17) from the French General Staff it is stated that it is quite out of the question for France to dispense with her supplies of ammonium nitrate.

2 We supplied 900,000 tons of coal and coke during 1917.


4. Laeso field.—This field includes four strips of territorial water, two of which present no serious difficulty to submarines on the surface:

(i) Land Deep, between Jutland and Laeso Channel light vessel (57° 13' N., 10° 42' E.).

(ii) Off Syr Point, the northeast corner of Laeso Island.

There is no good channel for neutral shipping, except the inner channel on the Swedish side, north of Varo Island (57° 33' X., 16° 48' E.).

This mine field, therefore, would obstruct neutral shipping and, if proclaimed, would not seriously incommode submarines unless the exits were patrolled.

5. Skaw-Patternoster[sic] field.—A clear passage must be left for neutral shipping both sides of the Skaw light vessel.

If territorial waters are respected, a channel must be left to the west and north of the Paternoster Rocks.

An inner channel passes west of Vanholmar Island (57° 57' N.. 11° 31' E.).

In view of the easterly set and the danger of passing close to the Paternosters in a westerly blow, it appears possible that neutral shipping would use the inner channel in preference, although local pilots would be necessary. The complete closing of this channel within the territorial limits might not therefore be greatly resented.

As the depth of water increases to the northward of the proposed field, it does not lend itself to reinforcement.

The current off the Skaw rises to 4 knots in gales, particularly from the west, but is normally 1 1/4 knots.

6. The Skaw field leaves one good exit and one awkward one unobstructed; the Laeso field, two good exits and two awkward ones, all being farther from British bases. The Skaw field is therefore considered the better one; but owing to the difficulty of patrolling neutral waters, neither can be considered as a satisfactory obstacle.

7. Details of proposed Skaw-Paternoster mine field.—

Safe channel: From Skaw light vessels to Laeso Trindel light vessel (139° true).

Southern boundary: 81° 6 miles from Skaw to 252° 3 miles from Paternoster Lighthouse. If it is decided not to respect territorial waters at this point, the mine field may be carried in as close to Paternoster Rocks as weather conditions at the time of laying permit.


H. 11, 150 feet apart in 5 rows, at 8, 38, 68, 98, and 128 feet; length, 18 miles:

Number of mines ........ 3, 600


Additional 2 rows, at 158 and 188 feet, closing the lower depths of Rannan Deep; length, 4 miles:

Number of mines__________________________________________ 320

Total mines______________________________________________ 3, 920

Dip, 1 foot in 50 fathoms; rise, 1 foot; probability for submarine on surface, 5 to 10 per cent.

8. If the field is carried into territorial waters at the Paternosters another 400 mines will be required.

9. Estimated time to lay 4,000 mines in this field.—If the mine layers Princess Margaret, Angora, Amphitrite, and Wahine were used, carrying 1,230 mines in all, the field would take three weeks to lay.

10. To complete the obstacle, patrols are required—

(a) Off the Skaw.

(b) Northwest of the Paternoster Rocks. (b) can not be carried out unless the weather is settled. It will be unnecessary if the weather is bad.

11. As the position of the mine field, when proclaimed, will be known to the enemy, he can only be stopped from sweeping it by regular patrols or checked by irregular raids. As there is little space for extending the field to the northward, it can not resist sweeping operations for very long.


[Appreciation by British Admiralty, Plans Division. February 7, 1918.]

Summary of Contents.

General situation.—The strategical aspect of the enemy’s submarine campaign. Its defeat depends on establishing a definite control over the North Sea exits. The Northern Barrage is a very important means to that end, but its success will depend entirely on the possibility of supporting the patrols in Area C. It is clearly demonstrated that this can not be done from Scapa or Rosyth and that, like a girder supported at one end, the plan will collapse unless a base is established in Norwegian waters.

General disposition for control of barrage.—Reasons why the establishment of a base in Norwegian waters will advance the Allies’ cause. Alternative proposals as to the size and nature of the detachment. Sums up in favor of battle cruisers, submarines, etc. Discusses the relative advantages of Skudaenaes and Selbiorns Fiord, and concludes that the former is preferable.

Patrol of the North-Sea barrage.—The part which the Grand Fleet plays in the control of the Northern Barrage is the crucial question in the 1918 antisubmarine campaign. Is the battle fleet to


be primarily disposed for securing the antisubmarine blockade, and the Grand Fleet destroyers employed hunting submarines where they will also be available to support the battle fleet in performing that function, or is it to be kept ready and equipped to dash after the High Sea Fleet, irrespective of the enemy’s object? If the latter course is followed and the patrol of the barrage is delegated entirely to trawlers and sloops, the submarine will probably continue to pass. It is suggested that the primary function of the Grand Fleet should be defined as the support of the barrage and the prevention of submarine passing out of the northern exit. This policy would entail the acceptance of certain minor risks which are dealt with in detail. Measures for strengthening the control of the southern area and east coast communications. Remarks on the patrol of the barrage. General strategical policy is summarized.

Political aspects of the question, etc.—The Norwegian people would have welcomed the seizure of a base early in 1917. The preservation of strict neutrality now the guiding idea of the Government. This change of attitude simplifies the situation in certain respects. Most important that the anchorage should be seized without any preliminary overtures. Norway’s probable attitude and possible courses of action. Arguments justifying the proposed course of action. International relations based on reciprocity; and to adhere to conventions, whilst the enemy abandons those that do not suit him, is suicidal. The rights of small nations can not be reestablished unless the submarine is defeated. The question of territorial waters. Analogy from the Helgoland Bight and enemy use of Danish territorial waters.

Decisions Required.

Decisions would appear to be necessary on the following points:

1. Is the 1918 antisubmarine campaign to be directed mainly toward obtaining a control of the North Sea exits?

2. If so, is a base in Norwegian waters necessary for the support of the patrols in Area C of the barrage?

3. If it is not necessary, how are the patrols to be supported?

4. If it is decided that a base is necessary, what is to be the size and nature of the detachment, and where is it to be based?

5. What are to be the functions of the Grand Fleet in the 1918 antisubmarine campaign?

6. If its correct functions are those suggested in this paper, is the control of the southern area to be strengthened by a modern battle squadron in the Swin, etc.?

7. If it is decided to seize an anchorage in Norwegian waters, when is it to be done, what procedure is to be followed, and what excuses are to be made ?


General Situation.

1. Attempts to defeat the submarine campaign mainly on a basis of local trade protection have been a failure, in the sense that if sinkings are not permanently reduced during 1918 the war will probably have an unsatisfactory ending.

2. Success in the future depends on the possibility of establishing control of the North Sea exits, conjoined with convoy protection.

3. It can not be too strongly emphasized that the enemy’s main line of strategy lies in submarine activity against commerce. If we vigorously oppose his submarines with mines, light craft, and aircraft, he will be forced to reply with light cruisers and destroyers. If we can drive these back he will be forced to bring out more powerful vessels, and finally his battle fleet may be drawn into the arena to decide the issue. This is briefly the strategical aspect.

4. The success then of the gigantic mining operations in the North Sea will finally depend on our ability to concentrate superior forces at any threatened point of the barrage.

5. The position of the barrage most liable to attack is that lying between 60 and 61° N.. and extending about 50 miles from the Norwegian coast (Area C). It is to be permanently patrolled by 24 trawlers, 6 sloops, and 1 bulged predreadnought battleship.

6. Their function is to drive the enemy’s submarines down to the deep mine field, which will extend across this area in 150 fathoms at a minimum depth of 65 feet below the surface. Also to hunt them with hydroplanes and depth charges.

7. It is doubtful whether 30 vessels can exercise this function over 3,000 square miles of water unless they compare very favorably with the submarines as regards speed and gun power; but this Is not the case, the ordinary U-boat being credited with 17 knots on the surface and a 4.1-inch gun, whilst the large submarine-cruisers carry two 5.9-inch.

8. It is unlikely that trawlers and a few sloops with a cruising speed of about 10 knots will force submarines to submerge over such a large area. On various occasions, both at home and abroad, trawlers hunting submarines have been able to do nothing when the latter have come to the surface and continued their journey. If the mine field is to fulfill its real purpose, destroyers must support the sloops and trawlers.

9. But whether these trawler patrols are able to make the enemy submerge or not, their presence will soon be known, and the whole system will break down unless they can be supported and strongly supported.

10. Ability to support the patrols depends upon our ability to concentrate superior forces against the enemy before he attacks, but, failing that, it will be possible to maintain the patrols if we can


intercept the enemy before he reaches the south of Norway on the return journey through the Kattegat.

11. As the distances from the Naze to the center of Area C, Rosyth, and Scapa are 190, 370, and 350 miles, respectively, this can not be done from Rosyth or Scapa unless early and accurate information is received of the enemy’s outward journey.

12. It is proposed to station submarines in a southwesterly direction from the Naze, but they will be submerged during the greater part of the day and will be practically useless at night as lookouts. Their hydrophones, which are supposed to detect surface vessels up to 10 miles, will be of very little service in this respect because they can not differentiate between types and numbers of ships.

13. If the support of the patrols in Area C is to be dependent on these submarines, and forces are to be rushed across the North Sea in response to vague, and possibly inaccurate, hydrophone reports, the supporting forces, as well as the trawler patrols, will be exposed to serious risks.

14. If the enemy brings out his battle cruisers, as he undoubtedly will sooner or later, their speed and gun power will render this blockade extremely hazardous and inefficient, unless the light craft are closely supported by capital ships.

15. The blockade force has the great advantage of the initiative. It can come out at any time of the night or day with concentrated forces tuned up to the highest point of preparedness, whereas the movements of the defending force are probably based on vague and inaccurate reports.

16. Under these circumstances a process of attrition will set in in Area C. Trawlers, sloops, and bulged battleships will, unless they are strongly supported, gradually disappear, whilst, even if early and accurate information is received of the enemy on his outward journey, Scapa or Rosyth are too far away to cover the large margin of error arising from limited visibility, enemy’s course alteration, and inaccurate dead reckoning of submarines and trawlers.

17. Nor can the patrols in Area C merely be ordered to retire to the northward on enemy movements being reported, for in that case he would achieve his purpose without having even to fight for it.

18. To summarize the above—the difficulty of supporting the patrols in Area C from Scapa or Rosyth will be very great indeed, and in default of other arrangements the Northern Barrage will probably fail, and the sinkings will consequently continue on a large scale during 1918. There appears to be only one solution, the establishment of a base in Norwegian waters.1


1 This question has been previously dealt with in the following Plans Division papers: Future policy, (a) 64 ; Naval policy, P. D. 06; Control of the Norway-Shetland-Orkney Area, (a) 166; Norway and the Allies, P. D. 31; Political effect on Denmark of the seizure by the Allies of a base In Norway, M. 016859: Northern Barrage, points for decision, M. 0917.


General Dispositions for Control of Barrage.

19. The expediency of seizing or acquiring a base in Norway will be considered later. Only its purely naval aspects are now under consideration.

20. The main argument in its favor is that it will consolidate the control of the northern area, on which the economical protection of the Allies’ commercial and military overseas communications largely depends, and will therefore greatly improve the general strategical situation.

21. It will also facilitate the control of the North Sea and east coast by making the Kattegat exit dangerous, thus confining raiders to the mined waters of the Helgoland Bight.

22. The ideal strategical distribution in the North Sea would be the Grand Fleet in Norwegian waters, with a detachment at Rosyth or in the harbor. But difficulties of supply and anchorage necessitate the main fleet being kept on this side, and in practice the best distribution appears to be the main fleet at Rosyth and a detachment capable of successfully engaging the enemy battle cruiser fleet, say, 5 powerful battle cruisers, with the Furious or other suitable aircraft carrier, 6 light cruisers, 10 destroyers, and 15 submarines in Norwegian waters.

23. This detachment, which would be as much part of the Grand Fleet as the battle cruiser fleet now at Rosyth, would prevent the enemy attacking Area C, except with strong forces, which would then be exposed to the danger of concentrated submarine attack and interception by the Grand Fleet.

24. A protective force of submarines would be required constantly at sea within 50 miles or so of the harbor and an airplane carrier capable of keeping up with the squadron would also be necessary. In case of attack by superior forces, the squadron would retire to the northward so as to give the battle fleet a better chance of cutting off the enemy.

25. As an alternative to this proposal, a battle squadron of eight powerful battleships, light cruisers, etc., might be substituted, the battle cruisers being retained with the main fleet. If the whole United States dreadnought fleet were sent over here,1 this would be a good deployment of our surplus battleships power. This squadron would also have to be protected from surprise by submarines and aircraft.

26. On the whole, the battle cruiser detachment appears to be the sounder of the two, but much may be said on the other side, and a decision would be necessary on this point (Point A—Strength and com-


1 This question has been previously raised in the following Plans Division papers: Cooperation of the British and American battle fleets, P. D. 05 ; Control of the Norway-Shetland Orkney area, (a) 100; Future- policy, (a) 64 ; Naval policy, P. D. 06.


position of eastern detached force). If the battle cruiser detachment is carried out, the question of strengthening it with Japanese battle cruisers is worthy of examination. Certainly, if the general plan is approved, every inducement should be offered to the Japanese to send these ships to the North Sea manned by Japanese.

27. The next question is that of bases. It is essential that the selected anchorage should be easily defended from submarines, and that superior forces attacking from the sea should be at a disadvantage. For reasons which will be given later, the anchorage must also be detached from the mainland and invulnerable to land attack.

28. There is a large anchorage in Skudesnaes Fiord, including Mastra Fiord (see Chart No. 1662, Skudesnaes Fiord, lat. 59° 4', long. 5° 46' E.) which fulfills all these requirements, and a detailed plan for its occupation and defense has been worked out. From this anchorages to the center of Area IV, Rosyth, and Scapa are about 100, 350, and 300 miles, respectively.

20. There arc also certain anchorages on the south side of the Selbiorns Fiord, such as Fitjebugten (see Chart No. 510, Hisken to Tofto), which appear to be suitable, but both in this case and the Skudesnaes Fiord the anchorages would have to be surveyed or swept before large ships could anchor in safety.

30. As far as the support of the barrage is concerned, a detachment in Skudesnaes is probably better placed than one in Selbiorns Fiord, but the latter is about 60 miles farther north and is less liable to surprise by superior forces. Skudesnaes is probably the better anchorage and is on the whole considered to be the more suitable of the two.

A decision is required on this point (Point R—Choice of Selbiorns Fiord or Skudesnaes.

Patrol or the North Sea Barrage.

31. It is believed that with the assistance of the mine barrage and a base in Norwegian waters the exits from the North Sea can be made so dangerous as definitely to defeat the submarine campaign during the summer months.

32. But the task will be a difficult one, requiring a large force of ships, thorough organization, and the best executive talent of the Navy. A large proportion of these elements are locked up in the Grand Fleet, and it appears that the success or failure of the barrage will depend upon them being partly freed for antisubmarine operations.

33. If the antisubmarine campaign is definitely accepted as the primary task, the battleships of the Grand Fleet will be mainly disposed to engage enemy surface vessels trying to break the antisub-


marine blockade, and its destroyers and other resources will be used for hunting submarines.

34. If, on the other hand, the governing factor is the desire to engage the High Seas Fleet irrespectively of the enemy’s object or locality, its dispositions and movements will be dictated from Wilhelmshaven, its destroyers being reserved for an action which may never take place.

35. The High Seas Fleet being the power behind the submarine, its destruction is very desirable. It can not be forced to fight, however; and in order to develop our maximum efforts against the submarines it is necessary to combine offensive antisubmarine measures with a defensive attitude toward the High Seas Fleet. The Grand Fleet must be prepared to fight and defeat the enemy, but under our conditions of time and place.

36. The submarine is the active and principal weapon of the German Navy; and until the Grand Fleet combines with the remainder of the British Navy to defeat the submarine, the High Seas Fleet can hardly be expected to accept battle. The submarine will probably not be defeated if the patrol of the barrage is delegated to trawlers and sloops, largely manned by unskilled and untrained officers and men.

37. If all the power and resources of the Grand Fleet arc concentrated on securing the control of the northern area, the enemy must endeavor to break down the blockade; and sooner or later the High Seas Fleet will come out and fight in the area where our destroyers are available both for hunting submarines and supporting the Grand Fleet in battle. Thus he will be forced to conform to our plans or admit the defeat of the submarine.

38. But this policy involves certain risks; for, if an intensive patrol is to be exercised in the north, the Grand Fleet, deprived of a proportion of its destroyer strength, can not be expected to dash south in the event of an enemy force threatening the Dover or Thames approaches. It is presumably this idea of a rush to the south that has tied up from 40 to 60 destroyers at Scapa and Rosyth, whilst enemy submarines are continually passing within 100 miles of the former port without any systematic attempt to hunt them.

39. To guard against this risk, it is proposed that a squadron1 of 4 to 8 dreadnought battleships should he stationed in the Swin to consolidate the control of the vitally important Dover and Thames area and to support the Harwich and Dover light forces; thus the enemy would have to expose considerable forces to submarine attack in order to raid this area. There would be no difficulty in providing this


1 The strength of this squadron to be governed by the consideration that the superiority of the Grand Fleet must not be imperiled.


squadron if all the United Slates dreadnoughts joined the Grand Fleet.

40. In the comparatively narrow waters of the southern area submarines and mines also act as a deterrent to enemy raids; and provided there is a high degree of cooperation among them and the surface and aerial craft on the south and east coasts, the Grand Fleet can be safely freed from the responsibility of dealing with battleship and battle cruiser raids in the south; but plans alone are not sufficient; the operations must be examined and practiced by the flag officer who is to execute them in face of the enemy.

41. Further, with a large proportion of its destroyers allotted to antisubmarine warfare, the Grand Fleet can not be expected to protect the east coast from battle-cruiser raids. These, however, should be viewed as diversions designed to immobilize destroyers from antisubmarine work or to draw the fleet into mined and submarine traps. After educating the public to this effect, they should be left to the local mine and submarine defenses. These raids (as well as attacks on the east coast trade) could be made extremely dangerous to the enemy by laying a few thousand mines off the vulnerable east coast points; 10,000 would suffice to lay a continuous line from the Humber to St. Abbs Head.

42. If the enemy attempted the extremely improbable operation of landing an invasionary army on the east coast, the Grand Fleet would, of course, have to move south as rapidly as possible after collecting a sufficient force of destroyers. Air reconnaissance should be able, however, to obtain at least 12 hours’ warning of any such operation, and the mere fact that 150 machines could be concentrated to bomb the beaches and transports within 12 hours, to say nothing of attack by submarines, might render the presence of the Grand Fleet unnecessary. If the operation were organized and prepared it is estimated that something like 400 airplanes and seaplanes could be assembled within 24 hours.

43. It is evident that if the foregoing policy is to be adopted all plans in connection with the control of the barrage must be drawn up under the direction of the commander in chief, Grand Fleet, the main function of the Admiralty being to define the general strategic policy and to supervise the disposition as a whole.

44. It may be suggested, however, that an elastic and variable system of patrolling will give the most satisfactory results, and that it will be better to concentrate strong forces in the areas where aircraft and other sources of information indicate the passage of submarines rather than to rely on any fixed geometrical distribution.

45. Groups of light cruisers and destroyers should be continually at sea, covering and assisting in the operations of the hunting flotillas, every possible use being made of aircraft and kite balloons.


Probably about one-half the destroyers would be in harbor resting and fueling, and they would be available to escort the battle fleet to sea in an emergency.

46. The general strategical policy which is proposed for the control of the Northern Barrage may be summarized as follows:

(a) The function of the Grand Fleet, including all available destroyers, trawlers, sloops, etc., to be defined as the support of the Northern Barrage and the prevention of submarines passing in and out of the Northern Barrage.

(b) A battle-cruiser detachment, with submarines, etc., to be based in Norwegian waters, in order to protect the eastern part of the barrage and to cover the Skagerrack passage. In the event of attack by superior forces it would refuse action, endeavoring to inflict damage with its submarine flotilla. It would be directly under the commander in chief, cooperating with the battle fleet in case of necessity.

(c) All available destroyers, trawlers, etc., supported by light cruisers, to be systematically used for hunting submarines in the northern exit., these forces being gradually strengthened from the convoys as the barrage commenced to take effect.

(d) The battleships generally to be based at Rosyth, but sometimes at Scapa, and always to be ready to offer battle in support of the antisubmarine operations, but not to move from its area of immediate control until it had collected and fueled a sufficient number of light craft.

(e) The control of the Dover area to be strengthened by stationing a modern battle squadron in the Swin, and the cooperation of all forces on the south and east coasts to be thoroughly organized and practiced, particular attention being paid to the use of mines for protection against coastal bombardments and to the organization of aircraft in case of attempts to land troops.

(f) It is not intended that this general policy should prevent the withdrawal of Grand Fleet forces for other operations initiated by the British, such as raids or antisubmarine operations in the Kattegat or Helgoland Bight.

Political Aspects of the Questions, etc.

47. The anchorages are situated between thinly inhabited or barren islands, and it would only be necessary to occupy a very small part of Norwegian territory. They are easy to defend, and only a few troops would be required.

48. So severely has Norway suffered from the submarine campaign that at one time the prospect of war with Germany was openly discussed in the Norwegian press, and there is reason to


believe that the occupation of a base by British or American naval forces would have been welcomed by the majority of the Norwegian people early in 1917.

49. Since then the collapse of Russia and other causes have diminished the prestige of the Allies, and the preservation of neutrality has apparently become the dominant aim of the Norwegian Government.

50. Some of the objections which were formerly offered to the occupation of a Norwegian harbor—e. g., the difficulty of guaranteeing her military assistance and protecting her coast from raids—were based on the assumption that Norway would openly join the Allies or at least tacitly agree to the infringement of her neutrality.

51. If a base were seized, however, in spite of Norwegian protests, the situation would be simplified, because Germany would have no legitimate excuse for bombarding her towns from the sea or air.

52. Neither Germany, Norway, nor Sweden could prevent the British Fleet making use of Skudesnaes once the anchorage was occupied. If Germany attacked Norway, it would merely stop her valuable Norwegian imports and might incur Swedish hostility. Germany could retaliate by seizing a south Norwegian port, but that would not interfere with our main object and her detached force would be exposed to considerable risks.

53. It seems most important from every point of view that the anchorage should be occupied without any preliminary overtures to Norway, and it is strongly urged that this course be followed. The possibility that Germany may forestall us and establish a submarine base at Skudesnaes must also be kept in view and is another reason against compromising diplomatic conversations.

54. The seizure of a Norwegian base primarily concerns this country, but the United States would have to supply the additional battleships for the Grand Fleet, and the few troops that would be necessary might be supplied by her in order to accentuate the temporary nature of the occupation.

55. If Norway is presented with a fait accompli, she will, no doubt, protest very vigorously, but taking into consideration her sufferings from the submarine campaign and her dependence on this country and the United States for food and coal, she will probably be inclined to accept the inevitable with a good grace.

56. Norway should under these circumstances be granted compensating advantages in the way of supplies. The Norwegian flag should continue to fly at the base and no allied flag should be allowed to fly on land. Sudden seizure, with a contemporaneous presentation of arguments, is infinitely better than negotiations, which might lead to preparations for defense, and bloodshed, which should be avoided at all costs.


57. As a protest Norway might refuse to trade with the Allies, but with a base at Skudesnaes we could in that case retaliate against German trade, and the result would be that Germany would suffer as much as ourselves and Norway would be worse off than either of the belligerents. If Norway continued to trade with us, it is proposed that her German trade should be allowed to continue.

58. We should be prepared for all these eventualities, but if a base in Norwegian waters is essential to the defeat of the submarine none of them should he allowed to influence the decision.

59. Justification for the proposed action is the next question. It would, of course, he an infringement of neutral rights, but in her submarine campaign Germany has definitely repudiated and abandoned the accepted rules of civilized war.

60. A well-known writer 1 on international relations points out that “the whole international code is founded on reciprocity,” and if an enemy violates the established usages of war his adversary may be forced by necessity to follow suit.

61. War is an appeal to force: and to adhere to conventions whilst the enemy abandons those that do not suit him is a suicidal policy.

62. The rights of small nations will not be reestablished unless Germany is punished for her violation of Belgium; and she will not he punished unless the submarine is defeated. The Northern Barrage will protect neutral as well as allied rights, and, if successful, will be welcomed by the Norwegian people; but whether it is or not, self-preservation is the first law of nature, and considerations of expediency are the only sure guide in the present case.

63. We should state that our object in seizing a base is to prevent the enemy evading our blockade by making use of territorial waters as a privileged channel of egress and ingress, and that we are forced to do it because we do not consider Norway strong enough to resist the passage of enemy submarines.2

64. It can be explained that when we mined the Helgoland Bight, Danish territorial waters were respected by us; but that the enemy submarines continually used them to avoid our mine fields and so obtained free passage to the high seas.

65. We should deny the right of an enemy to demand, under the pleas of international law and the immunity of territorial waters, a free and unrestricted passage to the ocean, there to wage war in defiance of all international law.

66. It should be explained that, in order to prevent such action on the part of the enemy, we are forced to establish a temporary control over Norwegian territorial waters which will only be directed against enemy belligerent vessels.


1 Treatise on International Law. Hon. Hannis Taylor, LL. D., 1902.

2 Reliable information indicates that the Norwegian Government would not resist the passage of enemy submarines through her territorial waters (vide M. 0917).


67. One thing is certain, that without a Norwegian base the Northern Barrage will be in the air, like some great girder supported only at one end.

[Extract from Memorandum No. 71, "History of Planning Section.”]

Initiated by the American Planning Section.

At the suggestion of the Force Commander, in order that he might better support our recommendations at the daily staff meeting at the Admiralty, it was proposed to the British Plans Division that this problem and future important problems be solved jointly by the two Sections.

The practice adopted was for each Section to reach a tentative solution independently and then to reconcile differences before preparation of a joint resolution.

The principal recommendation in this paper—i. e., to concentrate mining effort upon the Northern and Dover barrages, excluding any other mining that would interfere with these projects—was not accepted. The very extensive mining operations in the Bight then in progress were continued, and considerable mining in the Kattegat was undertaken subsequently. The American Planning Section always believed these efforts to be unsound, and so stated repeatedly and emphatically. It was apparent that closing either the Bight or the Kattegat was of little value unless both could be closed, and it was impossible to close the Kattegat without violating the neutrality of two Scandinavian nations. Furthermore, the proximity of these mine fields to enemy bases rendered impossible the prevention of enemy sweeping operations.

Undoubtedly some inconvenience was caused the enemy by this auxiliary mining. He sustained some losses in both fields. There were periods when weather prevented sweeping and when the danger of the passage through the Bight led the enemy to use only the longer Kattegat route. Nevertheless the auxiliary effort necessarily restricted the effort on the task of laying the Northern Barrage which promised much greater results than could be obtained by mining in the Bight and Kattegat.

The British mining activities during the war emphasizes the importance of—

(a) Formulating sound strategic policies and plans before undertaking operations.

(b) Concentration of effort.

Forwarding comment of the Force Commander on this paper follows: [Forwarded 18 April.]

“2. The Department is of course aware that there has been in the past very extensive mining in the Helgoland Bight, both by the British Admiralty and by the enemy. Mining in that locality is still carried on whenever circumstances appear to render it desirable, but it is not regarded as important us it was early in the war. There is a very large number of mines in this area and very few enemy submarines come out from Germany by this route.

“3. The Admiralty has also directed certain mining operations in the Kattegat with a fair degree of success. This work was begun about the end of March and has been carried on continuously when weather permitted.

“ 4. Mining has also been undertaken in the North Channel lending to the Irish Sea. It is upon this mining project that the U. S. S. Baltimore has been employed since her arrival in these waters.

“5. Laying mines in Area B of the Northern Barrage was begun by the British about three weeks ago, but owing to unexpected and unexplained difficulties


with the mines themselves the operations were suspended temporarily before one complete line had been run. Numerous mines failed to take the correct depth, a considerable number floated, and there were a number of premature explosions. H. M. S. Gaillardia, while accompanying a mine layer, was sunk by striking a mine.

“6. Since the British mine was supposed to be entirely safe if laid at a depth materially different from that intended, this behavior of the mines was very puzzling and disconcerting. A 35-foot sweep was made along the mines already laid, and a number of mines were picked up, although they were supposed to have been laid at a depth of 65 feet. Most of the mines that were picked up by the sweep exploded.

“7. The Commander in Chief of the Grand Fleet was naturally very much disturbed by these unsatisfactory results of the first mine laying, and the Admiralty have felt that they could not continue laying the barrage in Area B until the faults in the mines had been discovered and removed. I am not aware that they have as yet discovered what the difficulty is.

“8. With respect to Area B: I have from the first consistently urged that this area be made as narrow as was practicable, considering the requirements of the Grand Fleet and of commerce, and I have also held that the deep mining should be carried close up to the Islands of the Orkney group.

"9. With respect to Area C: I have equally held from the first that this could be made effective only by supplementing the deep mine field with a surface mine field of American mines, and that the mining should be carried up to Norwegian territorial waters, but not into them.

“10. My views with respect to Areas B and C have previously been accepted In principle by the Admiralty, and the department has been advised to be prepared to furnish surface mines for both of these areas.

"11. Owing to an apparent uncertainty in the Admiralty as to the further execution of the plans for the Northern Barrage, I caused the matter to be brought up at the staff meeting this morning, at which I proposed the following:

(a) We to lay two single lines of surface mines over the southern portion of Area C, 40 to the mile.

(b) British to lay one “system” of deep mines over the northern portion of Area C.

Note: A “system” of English mines comprises five parallel lines of different depths.

(c) We to run the two above-mentioned single lines in Area C and a single “system” entirely across Area A as early as practicable. Note: A “system” of American mines consists of mines at 80', 160', and 240' depths, respectively.

(d) Whether “C” or “A” is mined first is not very material, but if the mines and sinkers for Area C can be sent over without delay, it would be better to mine that area first.

(e) In view of the great difficulty of efficiently patrolling so wide an area as the present designed Area B, it seems necessary to surface mine a portion of it in the same manner as is proposed for Area C, leaving a portion without surface mines as an exit of the Grand Fleet, this exit to be as narrow as it can safely be made.

(f) Area B to be deep mined as already planned, except that the mines are to be carried close up to the coast (islands) without leaving the 7-mile channel now shown on the chart.

“12. Rear Admiral Strauss, commander of the mine force, was present at the meeting, and he and I were at entire concurrence at all points. The Admiralty


Staff did not reach a decision, owing, I believe, to their desire to consult the Commander in Chief, Grand Fleet, before reaching final decision. I have every reason to believe, however, that they will accede to all of the above proposals with the possible exception of (e).

“13. A proclamation notifying the mining of Areas A and C will be issued at an early date by the British Government.

“14. As soon as the proposal to lay a double row of surface mines across Area C is acceded to, I shall cable to the Department requesting that the necessary material be shipped."


Memorandum No. 18.


28 March, 1918.

[Study made preliminary to the joint consideration of British and American Sections.]



(See Maps Nos. 1 and 3.)

General situation: As at present. The shipping situation is becoming more and more critical. Unless a check is placed on the enemy’s submarines it may become necessary to cease the transport of United States troops and stores to France, in order to meet the urgent requirements of the Allies as regards food and raw material.

Special situation: The British and United States Planning Divisions decide to review the antisubmarine policy of the immediate future, bearing in mind that the Northern Barrage can not be moderately effective before July.

Required: Estimate of the situation and decisions as to antisubmarine measures that should be taken now.



To determine the best employment of our present forces to defeat the enemy submarine campaign.


Our present situation renders it imperative that we clearly recognize the import of our special and immediate naval mission, which has been determined previously to be—

“To obtain subsurface command of the sea while still retaining command of the surface of the sea.”

If the soundest employment of our forces is to be made, this mission must serve as the directive force for all allied naval activity; it must immediately become the basis for every naval plan of operations; to it must be referred every decision of importance; to it must be subordinated all other naval requirements for the time being.

The degree with which our command, high and low, becomes indoctrinated with the immediate importance of this mission will


determine the extent to which we make good use of the forces at our disposal.

It is apparent that an immediate acceptance of this mission will—

(a) Alter the primary role of the Grand Fleet from that of maintaining readiness to meet the High Seas Fleet on very short notice to that of combating enemy submarine activities.

Note.—It has been pointed out in a previous estimate that the enemy’s principal naval mission of preying upon our overseas communications will induce the High Seas Fleet to accept action only in support of his submarine campaign. It therefore follows that the Grand Fleet’s best chance of bringing the High Seas Fleet to action will flow from engaging in and supporting antisubmarine measures.

(b) Give an offensive tone to the efforts of all our forces engaged in antisubmarine warfare.

(c) Require that a considerable portion of our forces he allocated to offensive work.

(d) Require that our organization and allocation of forces, and our system of command of them, shall permit the most economical and effective antisubmarine use of the means at our disposal.

(e) Focus mining effort upon an attempt to exclude submarines from the high seas.

Note.—Examined in previous estimate.

(f) Focus naval air effort upon attacks on submarine bases, and restrict air patrols to areas where submarines are numerous.

Note.—Examined in a previous estimate.

(g) Require a development of our information service, such as will readily put our forces acting offensively in contact with hostile submarines.

(h) Require the development of doctrine such as will permit the ready coordination of units and of the various arms in combined offensive operations.

(i) Require a naval offensive against submarine bases where practicable.

Note.—The Adriatic is at present the only theater where this is practicable. This subject has been examined in a previous estimate.


Since we have examined already in other papers the best employment of mines and aircraft, as well as the value of an Adriatic offensive, the forces which we will consider herein as possibly available for reassignment of employment are—

(1) The Grand Fleet.

(2) District craft.


The Grand Fleet is practically now excluded from antisubmarine work, due to being held in readiness for quick action against the High Seas Fleet. In order to conform with our mission it is essential that all Grand Fleet units suitable and available for antisubmarine warfare be employed in such work. Other units of the fleet should furnish support to the antisubmarine forces in the northern theater.

Our district craft are comprised principally of types suitable for antisubmarine work—destroyers, P-boats, sloops, trawlers, drifters, etc.

They are distributed among nine principal districts about the coasts of Great Britain, and six on the French coast; each under a commander responsible only to the Admiralty (British or French, as the case may be).

These forces are employed almost exclusively in defensive work— patrolling and escorting. A few are engaged in supporting the Dover barrage. On April 1 there will be about 33 trawlers equipped with listening devices and supported by a few sloops engaged exclusively in hunting. It is expected to increase largely this force of hunting groups as new vessels are completed.

One of the principal virtues of the convoy system lies in the fact that, in order to attack, the enemy must come into close contact with our antisubmarine forces. In order to obtain the full value offered by these situations it is imperative that our forces temporarily divest themselves of their protective role and at once assume a vigorous offensive. At least half of the escorting vessels should engage in an intensified attack; and in the case of a small escort, all of the suitable ones should do so. The offensive operation should include not only an immediate depth-charge attack but also a persistent hunt during the remainder of that daylight by a large proportion of the escort. A doctrine along these lines should be promulgated at once.

It may be that the adoption of this general plan will prove our best course of action if at the same time accompanied by a redistribution of escort duties, so that escorts may be reduced in comparatively safe areas and increased in dangerous waters.

The value of a vigorous counterattack by a large proportion of each escort should be demonstrated by immediate trial.

Until this is done it will be difficult to decide whether to adopt such a course without reducing the total number of destroyers allocated to escort duty or to make such a reduction and assign the surplus to hunting duties.

Any radical and immediate change from convoy and escort work to hunting on a large scale must involve a large reduction in the numbers of craft, particularly destroyers, now assigned to convoy and patrol duties.


The justification for taking such steps will depend on—

(a) The extent to which mercantile losses will be increased by a reduction of convoy escorts.

(b) The probable destruction of enemy submarines and the extent of interference with their operations that will result from intensified hunting.

With regard to the probable effect on losses in convoy:

So long as the enemy continues his practice followed during the last six months of concentrating submarine operations within coastal waters, the destroyer offshore escort may be greatly reduced without materially affecting our losses. Similarly, destroyer requirements may be reduced by meeting convoys farther east than is now customary.

If in addition the doctrine be established of a vigorous counterattack and a determined hunt by a large portion of the destroyer escort on each occasion of an attack on a convoy, the number of attacks on convoys will be reduced.

For slow convoys, slow escorting vessels, such as trawlers, yachts, sloops, etc., may be taken from patrol work and substituted for destroyers.

Air patrols may be substituted for surface patrols along the coasts to a greater extent than at present by utilizing for patrol work our air pilots under training.

If these measures be taken, we believe that the present efficiency of the convoy system will not be materially reduced if we divert as much as 30 per cent of our destroyers from escort work to hunting. There arc approximately 400 British, American, and French destroyers operating in northern waters, so that about 120 should be available for hunting.

A still greater number can be made available by consolidating our coastal commands into a few groups, so that greater flexibility in operations and consequently more economical employment of forces is permitted. The following is suggested as a sounder grouping of command than that now in force:

1. Commander in Chief, Grand Fleet.—North Sea and antisubmarine operations from Firth of Forth north about to Hebrides, inclusive.

2. East Coast Command.—Coastal and antisubmarine work from Firth of Forth to Yarmouth.

3. Hinder Sea Command.—Yarmouth to Dover, inclusive.

4. Channel Command.—English Channel (exclusive of Dover), including French Channel forces.

5. Ireland Command.—Coasts of Ireland and approaches, including Irish Sea.

6. Biscay Command.—French west coast.


We therefore conclude that at least 120 of our destroyers may be diverted to hunting without material increase of mercantile losses. It is necessary to examine whether such an employment will he profitable.


If we can hunt the enemy to such an extent as to make him feel repeatedly harassed during long periods of time, we should gradually wear down his morale. We may expect the resulting nervous strain to cause accidents to and losses of boats due to internal causes, in addition to increased destruction caused directly by our own action.

Hunting will be most profitable—

(a) Over depths which forbid bottoming.

(b) During seasons of long daylight.

(c) During good weather.

(d) In areas not subject to much fog.

(e) Along routes leading to and from operating ground, where the direction of advance can be generally predicted.

(f) Against homeward-bound submarines, whose radius of action is restricted and who may be damaged.

Hunting will be facilitated by—

(a) A well-organized information system which will put hunting groups in touch with submarines. Present means of locating them should be augmented by a system of ground-listening devices around the Orkneys, Shetlands, and Hebrides.

(b) One or more airships or kite balloons in each hunting group.

(c) Listening devices carried by destroyers.

Note.—All new American destroyers will arrive equipped with an efficient device for short range. These destroyers should be assigned to this duty, if limiting by destroyers is decided upon.

The object of a hunt would be to destroy the submarine or to keep her submerged until batteries were exhausted.

Assuming visibility at 5 miles, a group of 18 destroyers can deploy so as to cover a circle of 25 miles radius. A submarine can reach the edge of this circle in 3 1/2 hours at 7 knots—batteries then exhausted; in 5 hours at 5 knots—batteries 40 per cent exhausted; in 12 hours at 2 knots—batteries 20 per cent exhausted.

Having deployed with center over the last known position of a submarine, the destroyers would then probably have from 5 to 12 hours of patrolling in which to sight or hear the submarine. Formation may then move its center over the new position and start afresh, with the advantage of having partially exhausted the submarine batteries. The operation may be repeated until the submarine must emerge. Meantime there may be opportunities for depth-charge attacks.


Should the hunters fail to sight the submarine by the end of the time when it is judged that the submarine may have run out of the patrolled area, an estimate must be made of the probable course and speed of the submarine and the formation as a whole moved accordingly. This estimate may be made with reasonable accuracy if the hunt is being conducted along the usual track between the submarine’s base and its operating ground and if it is known whether she is outward or inward bound.

In the event of fog or darkness the general formation should be preserved but each unit take up a wide zigzag, the formation as a whole advancing according to the estimated course and speed of the enemy.

Submarines have recently made such passages in groups of four or five. This will assist the hunters.

The chance of “getting” a damaged submarine by this means appears good. Some delay will be caused all submarines with which contact is made. Whether or not this general method will pay us in the case of undamaged submarines can be determined only by actual trials.

Trials should be begun at once with destroyers drawn from the Grand Fleet and not at present engaged in escort duties.

The data obtained will serve as a basis for future decision. Until such experience has been gained we can not afford the risk of radically reducing our convoy escorts.


1. To indoctrinate our command with the necessity for offensive antisubmarine effort whenever possible.

2. To make the primary mission of the Grand Fleet that of combating enemy submarine activity.

3. To immediately thin destroyer escorts for offshore convoy and thicken them in coastal waters.

4. To indoctrinate destroyer escorts so as to make their primary mission the counterattack and hunt of all submarines which may attack convoys.

5. To substitute trawlers, sloops, yachts, etc., for destroyers in escorting slow convoys as practicable.

6. To substitute air for surface patrols as practicable by utilizing air pilots under training for patrol duties.

7. To immediately reorganize our forces into six commands as follows:

(1) Commander in Chief, Grand Fleet.—North Rea and antisubmarine operations from Firth of Forth north about to Hebrides, inclusive.


(2) Hast Coast Command.—Coastal antisubmarine work from Firth of Forth to Yarmouth.

(3) Hinder Sea Command.—Yarmouth to Dover, inclusive.

(4) Channel Command.—English Channel (exclusive of Dover), including French Channel forces.

(5) Ireland Command— Coast of Ireland and approaches, including Irish Sea.

(6) Biscay Command.—French west coast.

8. To augment our present means of obtaining information of submarine positions by a system of ground listening devices around the Orkneys, Shetlands, and the Hebrides.

9. To immediately employ the Grand Fleet destroyers in hunting along northabout submarine routes between their bases and hunting grounds; hunting groups to include new American destroyers equipped with listening devices.

10. To employ airships and kite ball[o]ons in conjunction with hunting groups of destroyers.

11. To give further consideration, after experience in hunting has been gained, to the question of withdrawing a large number of destroyers from escort duties and of assigning them to hunting.

Joint Appreciation by the British and American Planning Divisions.

[March 28, 1918.]


Present policy.—Present submarine policy mainly a system of local trade protection. No concentrated attack on submarines, except in the Dover area. Convoy escorts have the great advantage of getting in touch with the submarines, but their tactics are generally defensive, and they seldom kill. Lack of cooperation characteristic of the present system.

Suggested modifications.—Immediate policy—a concentrated offensive in North Sea exits, combined with a modified system of local protection. An intensive patrol of the Fair Island Channel approaches. The functions of the Grand Fleet—the crucial question. The idea of inveigling the High Seas Fleet into a fleet action should be abandoned in favour of an antisubmarine blockade of the northern exit. The leadership and organizing power of the Grand Fleet higher command and staff, as well as a small proportion of its destroyers, are essential to effective antisubmarine measures. The ocean escort destroyers and the coastal trawler patrols reduced by 30 and 50 per cent, respectively, to obtain the remainder of the required forces. Probable effect of these reductions. Offensive meas-


ures on a small scale recommended in other areas to be brought about by a reorganization and consolidation of the coastal commands. Summarized conclusions.


1. The forces directly employed fighting the submarine are to be found in two organizations: Convoy escort vessels and auxiliary patrol craft, the former escorting ships through the submarine zone, the latter being distributed round the coast.

2. These forces are given in the following table under the headings “Escort duty,” “Patrols,” and “Mine sweeping.”

[S1 = Sloop; D1 = Modern destroyer, F. class and later; D2 = Older destroyer; P = P-boat; S = Submarine; T = Trawler; W = Whaler.]

Nature of work. S1. D1. D2. P. S. T. W.
Ocean escorts 24 1110 --  13 --  --  -- 
Cross-channel escorts --  1 12 31 --  246 -- 
Coastal escorts --  --  24 --  --  --  -- 
     Total escorts 21 111 36 44 --  246 -- 
Coastal patrols --  --  --  --  --  248 6
Submarine patrols --  --  --  --  38 --  -- 
Mine sweeping --  --  --  --  --  410 --

In addition to the above, a force of about 21 trawlers is being prepared, fitted with fish hydrophones, for submarine hunting.

1 Includes 38 United States destroyers at Queenstown and 6 destroyers at Granton for Scandinavian convoys. Does not include any of Harwich force, which nevertheless is employed as Dutch convoy escorts.

3. In addition to the forces in foregoing table there are the Grand Fleet and the Harwich and Dover forces. The task allotted to the Grand Fleet and its accepted policy is to be ready to engage the High Seas Fleet at anytime and anywhere in the North Sea.

4. The number of destroyers allocated to the Grand Fleet is only sufficient for battle purposes, and this policy, therefore, immobilizes them from any extensive or continuous antisubmarine operations.

5. In the south, on the other hand, the primary task is to bar the Dover Straits, and the primary function of the Dover and Harwich forces is to support the barrage. Dover, therefore, is the only area in which any concentrated attack is being made on the submarine. The results are seen in Appendix I, which shows the soundness of this policy.

6. It is clear that the vast majority of the antisubmarine forces in the vicinity of the United Kingdom are spread over a wide field and arc not concentrated to attack submarines. We try to be strong everywhere, and are strong nowhere.

7. Part of the protective system, viz, the escort of convoys by fast vessels, has, however, the great advantage of forcing the submarine


to attack in the vicinity of the escort, and gives it a chance of counterattack. In practice, however, only a few submarines are destroyed under these circumstances. This may be due to the fact that the forces on the spot are insufficient to bring about results.

8. It may also be due to faulty tactics, and in order that full advantage may be taken of these contacts, it appears essential that the escorting destroyers should drop the defensive role and assume a vigorous offensive, which should not only include an immediate depth-charge attack but also a persistent hunt during the remainder of the day by a large proportion of the escort. The question whether any destroyers should remain with the convoy would depend on the locality and probability of further attacks.

9. So far as trawlers are concerned, they have little offensive value, except in cooperation with faster vessels, and this emphasizes the necessity of coordinating the work of all craft and weapons. Each type possesses a certain degree of offensive power, but unless these powers are used in combination, successful results can not be expected. The deep mine field is dependent upon surface patrols. Hydrophone trawlers are practically useless without faster vessels, and aircraft greatly increase the hunting power of destroyers.


10. Instead of the above system of dispersion of force, it is urged that we should eventually aim at closing the northern exit by a great offensive effort in that area.

11. Decisive results will not be obtained until a very strong mine barrage is completed, and it would be inexpedient to abandon the local protection of trade until the hydrophone is more fully developed. It is urged, however, that a concentrated offensive effort, covering the reported track of submarines, be instituted in the northern area as soon as possible.

12. In February about 70 per cent of the submarines operating outside the North Sea passed northabout, and the number will tend to increase. Also, a certain number were probably damaged or defective on reaching this area, homeward bound.

13. At the present time submarines passing northabout confine themselves almost exclusively to the Fair Island Channel, the passages averaging one a day during February, 1918. The approximate times of passing through the channel arc shown graphically in Appendix II.

14. An intensive patrol in this area could be quickly moved to another track, and would be flexible in its dispositions, enabling the utmost use to be made of any information available, which, at present, is certainly not utilized to its fullest extent.


15. It is most strongly urged that the success of the above policy rests on allotting certain definite antisubmarine functions to the Grand Fleet, for unless its present functions are modified, neither sufficient destroyers nor the necessary standard of organization will be forthcoming.

16. So long as the movements and dispositions of the Grand Fleet are based on the idea that the High Seas Fleet is likely to be inveigled into action by any other means than the defeat of the submarine, the most efficient part of the British Navy must play a comparatively minor part in defeating the enemy’s primary line of attack. It must stand aside and leave the real battle to the militia of the sea—the trawlers, mercantile marine, etc.

17. On the other hand, if the primary function of the Grand Fleet during the summer months is defined as the barrage of the northern exit to submarines, the High Seas Fleet will only become an object of immediate attack if it threatens the barrage.

18. The proposed policy amounts to exercising an intensive and immediate control over the northern area, while the control over the rest of the North Sea will be less immediate and less intensive. It involves certain minor risks, such as exposure to bombardment, etc. These risks, which have been referred to in other papers, should be accepted and the necessary precautions taken. (Vide P. D. papers 049, 37, and 053; also American P. D. Problem No. 2.)

19. By assembling the whole Grand Fleet at one base, and freeing it from the responsibility of dashing after the High Seas Fleet at short notice, except in support of antisubmarine operations, a flotilla of destroyers could probably be released for hunting submarines, but the commander in chief might allocate more or less, according to circumstances.

20. In order to provide the remainder of the antisubmarine destroyers and patrol craft, it is proposed to reduce the escort destroyers, sloops, and P-boats by approximately 30 per cent and the trawlers round the coast on patrol duties by about 50 per cent.

21. The withdrawal of trawlers from coastal patrol will probably not influence the shipping losses one way or the other. The effect of reducing the convoy destroyers can not be exactly foreseen, but no appreciable increase in sinkings is expected. The great initial success of the convoy system was due more to the concentration of shipping in a comparatively small space, and the consequent difficulty of locating it than to the protective power of the escort. This is illustrated by Appendix III, which shows how the enemy attempted to meet the convoy system by transferring his attack to the coastal and terminal areas, where his submarines would have a better chance of


finding the convoys; also, by the fact that out of 57 attacks in which torpedoes were fired on ocean convoys between July, 1917, and March, 1918, in only two cases did the escort sight the submarine before the torpedoes were fired.

22. The proposed reduction in destroyer escorts might be compensated by increasing the destroyers in the dangerous zones at the expense of the comparatively safe areas. For example, whilst the submarine campaign is mainly confined to the coastal areas of the United Kingdom, escorts to the westward of, say, 10° W. might be greatly reduced.

23. In addition to the proposed operations in the northern area, it is suggested that yachts, older destroyers, and the remaining trawlers employed on coastal patrols should carry out similar operations on the east coast, Channel, and Irish Sea, in conjunction with drifters and mined nets, and that the coastal commands be consolidated into a few groups, so as to obtain greater flexibility and more economical employment of the available forces. The following grouping is suggested:

(1) Commander in Chief, Grand Fleet.—North Sea and anti submarine operations from Firth of Forth northabout to Hebrides, inclusive, with particular regard to the blockade of the northern exit.

(2) East Coast Command.—Coastal antisubmarine work from Firth of Forth to Yarmouth.

(3) Narrow Seas Command.—Yarmouth to Dover, inclusive, with particular regard to the blockade of Dover Straits.

(4) Channel Command.—English Channel (exclusive of Dover), including French Channel forces.

(5) Ireland Command.—Coasts of Ireland and approaches, including Irish Sea.

(6) Biscay Command.—French west coast.

Under the present system of scattered coastal commands, it is most noticeable that submarines frequently operate for days in very limited areas without any large forces being brought to the spot, although they might be concentrated in a comparatively short time.

24. The foregoing may be summarized by saying that the principal factor in the solution of the submarine problem is a new orientation of the functions of the Grand Fleet, and that if the commander in chief is allotted the primary task of preventing submarines passing northabout, and is freed from responsibilities which interfere with that duty, everything else will follow in due course. A consolidation and reorganization of the coastal commands are also required.


Appendix I.

[From information supplied by I. D. Section 25.]

Comparison of passage (submarines) through Dover Straits and northabout.

  Northabout. Dover.
Out 10 25
Home 13 13
Out 12 8
Home 7 9
Out 18 5
Home 11 7
Mar. 1-15:  
Out 7 6
Home 14 2

Comparison of passages (large submarines only)

  Boats. Passages. Northabout. Dover.
December 21 42 17 19
January 13 26 18 5
February 21 42 39 1

No large submarines are believed to have passed through Dover Straits since the 18th of February.

Appendix III.

Statement showing British merchant steamships over 500 tons gross sunk by enemy submarines in home waters during 11 months ended December, 1917, divided as to distance from nearest land.

[Convoy system commenced on a large scale in July, 1917.]

Distance from nearest land.
Month. Within 1 mile. 1-2 miles. 2-4 miles. 4-6 miles. 6-8 miles. 8-10 miles. Total under 10 miles. 10-50 miles. Over 50 miles. Total.
February --  1 7 2 1 5 16 17 16 49
March --  1 5 5 5 18 28 20 66
April --  1 1 2 3 1 8 12 63 83
May --  1 2 2 7 6 18 12 22 52
June --  1 --  4 1 1 7 9 46 62
July --  --  3 1 1 2 7 13 33 53
Total --  5 18 16 15 20 74 91 200 365
Average per month --  1 3 3 2 3 12 15 34 61
Percentage of total --  --  --  --  --  --  20 25 55 100
August --  2 5 6 7 3 23 16 11 50
September --  2 4 2 3 1 12 8 4 24
October 1 3 6 4 4 9 27 12 1 40
November --  5 6 3 3 5 22 8 --  30
December 2 1 13 4 2 4 26 21 1 48
Total 3 13 34 19 19 22 110 65 17 192
Average per month --  3 7 4 4 4 22 13 3 38
Percentage of total --  --  --  --  --  --  58 34 8 100

[Extract from Memorandum No. 71, “History of Planning Section.”]

Initiated by the American Planning Section; solution submitted jointly by American and British Sections.

The principal points of difference between the preliminary Independent solutions of the two sections were:

(a) British solution included proposed tactical plans in some detail for hunting with a large group of about 20 destroyers (suggested originally by American Planning Section), and for an elaborate patrol of trawlers, P-boats, etc., in the approaches to the Fair Island passage. We believed these proposals somewhat academic in form and concurred only in the general recommendation that operations of that nature be undertaken. The appendixes on these subjects were therefore omitted from the joint solution, though submitted to the Admiralty independently by British Plans Division. The patrol was subsequently instituted off Fair Isle, and, after several months’ trial without any greater success than occasional contacts with enemy submarines, was abandoned.

(b) The British desired to divert at once large forces from convoying to hunting. The Americans desired to divert at first sufficient forces only to demonstrate the value of hunting, and if results warranted, then to increase hunting forces gradually at the expense of convoying. In reconciling differences this point was conceded to the British.

This paper caused much comment among British officials—principally unfavorable, on account of the recommendation that convoy escort forces be reduced.

The Force Commander took the view that any extensive reduction of convoy escorts was unwarranted and highly dangerous, and that hunting which depended principally on sight was futile.

Admiral Sir Lewis Bayly, Commander in Chief, Coast of Ireland, is reported to have said that to reduce the convoy escorts would be to “tamper with the safety of the Empire.”

It is understood that the Commander in Chief, Grand Fleet, was in accord with the idea of giving him command of the antisubmarine measures at the northern exit to the North Sea, but was not willing to undertake such a task without an increase in the antisubmarine forces, particularly destroyers, assigned to him.

The written comment of the Deputy Chief of Naval Staff follows:

"The analyses in Appendixes I and III are most instructive. Three points can be deduced from them, and in any discussion of submarine measures they should be taken into account:

“(1) The effectiveness of the Dover patrol has increased enormously; this combined with the intensive mining of the Bight has had the result of deterring submarines from attempting the Dover passage. More submarines proceed northabout, and urgency of offensive operations in the north is enhanced.

“(2) The convoy system has had the effect of causing the vast majority of successful attacks to be made comparatively close to the coast.

"(3) The above fact has rendered possible more concentration of antisubmarine force, and in areas more favorable for its operation. Consequently losses have diminished.

“With the general policy advocated in this paper I am in agreement. The trend of the remarks on the function of the Grand Fleet appears to be somewhat academic. The state of preparation of the Grand Fleet must be in every respect the same if it is to engage the High Seas Fleet, whether it is to do so


'at any time or anywhere in the North Sea,’ or only ‘if it threatens the barrage,’ since there is no more reason to expect warning if the High Seas Fleet comes out to operate in the south than if it comes out to operate in the north.

"I do not agree with any reduction of convoy escorts; indeed, if it were possible, which it is not without detriment to other services, I would increase them in order that a margin of force might be available to attack a submarine which has attacked a convoy.

"I do not agree with the statement in paragraph 5 that the primary function of the Harwich force is to support the Dover barrage. It is rather to interfere with any operations in the southern area of the North Sea which the enemy may attempt with light forces and to observe any movements of his heavy forces in the southern area.

“Propose that the paper be taken to the Commander in Chief, for VA northern patrol, for his perusal.

“S. R. F.’’

The written comment of the Assistant Chief of Naval Staff is quoted below:

“I would suggest that Plans should supplement this interesting study with a thorough investigation of the antisubmarine policy at the moment. A study of the measures in force and in preparation, with the actual employment of the forces available and the reasons underlying their employment, would show that many of the proposals have been anticipated and either are in operation or in process of being put in operation when the necessary resources, provision for which we made many months ago, materialize.

“The paper would have been more valuable had it been written in connection with the departments who from day to day study the varying aspects of the submarine situation and the most effective methods of dealing with it.”

The forwarding comment of the Force Commander on 29 May follows:

“2. This paper is forwarded as a matter of interest to the Department, although it docs not meet with my entire approval. Few of the recommendations have been put into effect.

“3. Viewing the paper broadly, it proposes three radical changes from the present practice, viz:

(а) A change in the mission and functions of the British Grand Fleet.

(b) A reduction of danger zone escorts by 30 per cent

(c) A reduction in coastal patrol by 50 per cent.

“4. It would, perhaps, be nearer the mark to state instead of (a), above, that the proposal is to effect a change in the Commander in Chief's conception of his own mission and to cause him to feel the same responsibility for closing to submarines the northern exits from, the North Sea as is felt by the vice admiral at Dover to close the Dover Straits.

"5. It is, of course, not proposed that the capital ships of the Grand Fleet shall engage in antisubmarine warfare. The destroyers and other vessels of similar types now attached to the Grand Fleet and needed for screening purposes would, of course, be very useful in assisting to close the northern exits from the North Sea and in an antisubmarine offensive. Their allocation to this sort of employment would necessitate putting the battleships into one or two harbors on about 20 hours' notice for sea instead of 4 hours as at present. The result of such action might conceivably be a very serious raid on the east coast of England by the enemy’s High Seas Fleet, of which the political if not the military results would be most harmful to the allied cause.


“6. It is difficult to say just what the size of an escort should be for a convoy of a given size, and it may be that it is the presence of escorting vessels rather than their number that deters the submarine from attacking. We have no assurance of this, however, and must assume the contrary. It is, therefore, not wise at present to reduce the strength of escorts.

"7. The coastal patrols might perhaps be reduced without loss of efficiency if a vigorous offensive were directed against submarines in other areas, but unfortunately vessels of the class engaged in this patrol work are the least efficient for offensive operations, having low speed and offensive power.

“8. The laying of the mine barrage across the North Sea will begin very soon, but, owing to defective functioning of the British mines, the deep mining of the section of the barrage nearest the Scottish coast can not be undertaken at once, so that the only means for preventing the passage of submarines across that area will be the establishment of a patrol. Whether or not this can bring the decisive results contemplated by Paragraph II of the inclosed paper is questionable. Certainly no extensive reduction in the protection now given to shipping could he considered, unless we could be assured that both the Dover Strait and the northern exit from the North Sea were closed with a reasonable degree of tightness against the passage of submarines.

“9. With respect to the suggestions in Paragraph 23: I am quite in agreement that the present division of command about the British Isles is not a satisfactory one, nor one that is conducive to the highest efficiency, but this is, of course, a matter so intensely domestic in its nature that the Admiralty could not be approached on the subject in any official way. I believe the Admiralty itself is not satisfied with the division of command in the Channel, and it is probable that some change will be made in the near future.

“10. A considerable amount of effort has recently been devoted to an attempt to prevent the passage of submarines through the Fair Island Passage, or to operate offensively against any that may use that passage. There have been some encounters with submarines in that locality without definite results, and it is supposed that recently the German submarines have been acting under orders to avoid that passage by going north of the Shetland Islands.

"(Sgd.) Wm. S. Sims.”


Memorandum No. 19.


26 March, 1918.



General situation: United States naval forces afloat in European waters are as at present, with the expected addition of 144 submarine chasers, 100 Ford destroyers, and new destroyers at an average rate of six a month. United States naval aviation forces at 15 stations on shore.

Required: An organization of forces, together with the principles that shall govern their administration.



(a) “The Organization of United States Fleets” of November 3, 1917, with corrections, and General Order No. 218, have been used as the basis of the within organization.

(b) Vessels not built for naval use, but capable of similar employment, have been grouped together in tactical units.

(c) Commanders of naval forces who have their administrative headquarters habitually in port have been given geographical titles.

(d) Commanders of naval forces having their administrative headquarters on mobile units may be given titles based on the character of the task of the forces they command; but tactical titles in accordance with General Order 218 shall be made to serve wherever possible.

(e) In administering the organization, the principle of continuity of association should govern as far as possible. This is of particular importance in the destroyer force. To this end transfers to new operating areas should be made by divisions. While operating in any one area there should be a constant effort to keep vessels of a division working together at sea, no matter what the duty they may be per-


forming. The fixed pursuit of this policy will build up teamwork and constant readiness for new employments.

(f) We recommend that the destroyers he reassembled in divisions indicated, according to their characteristics; and that in future the departmental organization be maintained, as confusion is bound to result from any departure from the department’s organization when the forces involved are as numerous as they soon will be.

(g) We recommend that no more vessels be assigned to escort work, but that accretions to the force be used in continuous offensive work.

(h) In the organization sheets of naval forces afloat that follow the pages are numbered to correspond with the sheets they should replace in the “Organization of United States Fleets” of November 3, 1917.


Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Squadron Four.  
Division Nine.  
Flag New York   Grand Fleet.
  Wyoming   Grand Fleet.
Florida   Grand Fleet.
Delaware   Grand Fleet.
Texas   Grand Fleet.
Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Squadron Two.  
Division Four.  
  Birmingham   Ocean Esct. Gibraltar.
Chester   Ocean Esct. Gibraltar.
Salem   Not yet arrived.



Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Division Five.  
  Machias   Zone Esct. Gibraltar.
Castine   Zone Esct. Gibraltar.
Paducah   Zone Esct. Gibraltar.
Wheeling   Azores.
Nashville   Zone Esct. Gibraltar.
Sacramento   Ocean Esct. Gibraltar.
Division Six.  
  Seneca   Ocean Esct. Gibraltar.
Tampa   Ocean Esct. Gibraltar.
Ossipee   Ocean Esct. Gibraltar.
Yamacraw   Zona Esct. Gibraltar.
Manning   Ocean Esct. Gibraltar.
Algonquin   Ocean Esct. Gibraltar.
Squadron Three.      
Division Seven.      
  Corsair   Offshore Esct. Verdon.
Aphrodite   Offshore Esct. Verdon.
Noma   Offshore Esct. Verdon.
Wakiva II   Offshore Esct. Verdon.
May   Offshore Esct. Verdon.
Division Eight.  
  Christabel   Coastal Esct. Brest.
Wanderer   Coastal Esct. Brest.
Emeline   Coastal Esct. Brest.
Remlik   Coastal Esct. Brest.
Sultana   Coastal Esct. Brest.
Harvard   Coastal Esct. Brest.
Division Nine.  
  Corona   Coastal Esct. Brest.
  Rambler   Coastal Esct. Brest.
  Victorine   Coastal Esct. Brest.
  Vidette   Coastal Esct. Brest.
  Nokomis   Coastal Esct. Brest.
  Piqua   Coastal Esct. Brest.
Squadron Four.  
Division Ten.  
Anderson   L’Orient Mine Swprs.
McNeal   L'Orient Mine Swprs.
Cahill   L’Orient Mine Swprs.
James   L'Orient Mine Swprs.
Division Eleven.      
  Hinton   L’Orient Mine Swprs.
City of Lewes   L'Orient Mine Swprs.
Douglas   L’Orient Mine Swprs.
Hubbard   L'Orient Mine Swprs.
Courtney   L’Orient Mine Swprs.


Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Division Twelve.  
Squadron Five.
Division Thirteen.
  Yankton   Gibraltar.
Surveyor   Zone and Oran Escort.
Nahma   Zone and Oran Escort.
Lydonia   Zone and Oran Escort.
Arcturus   Zone and Oran Escort.
Venetia   Zone and Oran Escort.
Cythera   Zone Escort.
Wenonah   Zone Escort.
Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Flotilla A.
Division A.
  Stewart   Brest.
Whipple   Brest.
Truxtun   Brest.
Macdonough   Brest.
Worden   Brest.
Division B.  
Division C.  
  Barry   Gibraltar.
Decatur   Gibraltar.
Dale   Gibraltar.
Bainbridge   Gibraltar.
Flotilla One.  
Division One.  
  Smith   St. Nazaire Escort.
Flusser   St. Nazaire Escort.
Lamson   St. Nazaire Escort.
Preston   St. Nazaire Escort.
Reid   St. Nazaire Escort.
Isabel   St. Nazaire Escort.


Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Division Two.  
  Monaghan   Brest Escort.
  Roe   Brest Escort.
  Terry   Queenstown.
  McCall   Queenstown.
  Jouett   United States.
  Beale   Queenstown.
Division Three.  
  Paulding   Queenstown.
Jenkins   Queenstown.
Walke   United States.
Warrington   Brest.
Sterrett   Queenstown.
Drayton   Brest.
Tender Dixie    
Flotilla Two. Division Four.  
  Burrows   Queenstown.
Trippe   Queenstown.
Ammen   Queenstown.
Patterson   Queenstown.
Fanning   Queenstown.
Jarvis   Brest.
Division Five  
  Balch   Queenstown.
Aylwin    Channel.
Duncan   Queenstown.
Downes   Queenstown.
Division Six.  
  Cassin   Queenstown.
Cummings   Queenstown.
Parker   Queenstown.
Benham   Queenstown.
Tender Melville    
Flotilla Three.  
Division Seven.  
  O'Brien   Queenstown.
Nicholson   Brest.
Winslow   Queenstown.
McDougal   Queenstown.
Cushing   Queenstown.
Ericsson   Queenstown.


Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Division Eight.  
  Tucker   Queenstown.
Conyngham   Queenstown.
Porter   Queenstown.
Wainwright   Queenstown.
Wadsworth   Brest.
Division Nine.  
  Sampson   Queenstown.
Rowan   Queenstown.
Davis   Queenstown.
Allen   Queenstown.
Wilkes   Queenstown.
Shaw   Queenstown.
Flotilla Four.  
Division Ten.  
  Stockton   Queenstown.
Caldwell   Queenstown.
Connor   United States.
Manley   Queenstown.
Gwin   United States.
Division Eleven.  
Division Twelve.  
Flotilla Five. Division Thirteen.  
Division Fourteen.  
Division Fifteen.  


Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Flotilla Two. Division Four.  
Support Tonopah   Azores.
Tender Fulton   Azores.
  K-1   Azores.
K-2   Azores.
K-5   Azores.
K-6   A zorcs.
K-1   Azores.
E-1   Azores.
Division Five.  
Tender Bushnell   Berehaven.
  A. L. 1   Berehaven.
A. L. 2   Berehaven.
A. L. 3   Berehaven.
A. L. 4   Berehaven.
A. L. 9   Berehaven.
A. L. 10   Berehaven.
A. L. 11   Berehaven.
Assignment. Ship. Flag officer and comdg. officer. Remarks.
Mine Planters.  

San Francisco    
Shawmut   ex S. S. Massachusetts.
Aroostook   ex S. S. Bunker Hill.
Canandaigua   ex S. S. El Siglo.
Canonicus   ex S. S. El Cid.
Housatonic   ex S. S. El Rio.
Roanoke   ex S. S. El Dia.
Quinnebaug   ex S. S. Jefferson.
Saranac   ex S. S. Hamilton.
Bridgeport   ex S. S. Breslau.
Black Hawk   ex S. S. Santa Catalina.
Mine Sweepers.  
Assignment. Ship. Flag officer and comdg. officer. Present assignment.
  Prometheus   Repair ship, Brest.
Panther   Repair ship, Brest.
Carola IV   Barrack ship, Brest.
Concord   Tug, Brest.
Montauk   Tug, French Coast.
Barnegat   Tug, French Coast.


Assignment. Ship. Flag officer and comdg. officer. Present assignment.
  Gypsum Queen   Tug, French Coast.
Nahant   Tug, Genoa.
Penobscot   Tug, Genoa.
Druid   Barrack ship, Gibraltar.
Margaret   Azores.
Galatea   Azores.
Marietta   Gibraltar, to go to Azores.
Santee   Repairs.
Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Squadron Two.  
Squadron Tender.  
Division Four.  
Division Five.  
Division Six.  
Assignment. Ship. Flag officer and comdg. officer. Present assignment.
Squadron One.  
Division One.  
Division Two.      
Division Three.      

Memorandum No. 20.


3 April, 1918.

(For joint appreciation by British and American Planning Sections, see Memorandum No. 20 A.]


Subject: Doctrine that should govern the action of escorting vessels (destroyers, trawlers, and P-boats) when contact with an enemy submarine is made in the vicinity of a convoy.

The following is a paraphrase of a report recently received concerning the contact of an escorting vessel with an enemy submarine:

At 10.45 a. m., while in position 3

8 miles ahead, and zigzagging at 13 (?) knots across the front of convoy ----------, a disturbed oil streak was observed crossing the front of the convoy in a southwesterly direction, convoy steering 54 S. E. Proceeding to investigate, the ship was maneuvered into a position alongside and parallel to this streak, increasing to full speed (about 17 knots). Shortly after the streak took a turn 90o to starboard, running parallel to the convoy at a distance of about 1 mile from it.

It being undoubtedly the wake of a submarine, on obtaining a position about 50 yards ahead of the end of the wake (which was clearly defined) a Type “D” depth charge was dropped, set to 100 feet; this exploded well. We then turned around and passed over the spot where the depth charge had exploded, clearly marked by the usual brown deposit, etc., the residue from a depth charge exploding, and observed a bright streak of fresh oil moving slowly away. Ahead of this, at 11.15 a. m., another Type “D" depth charge was dropped, set to 100 feet; this also exploded. Turning round again, fresh streaks of strongly smelling oil, together with bubbles and a disturbance in the water, was noticed, and a third depth charge, set to 150 feet, was dropped on this position. After the explosion the ship was brought over this spot at slow speed; much strongly smelling oil and a small quantity of bubbles were coming to the surface.

As the convoy was now at a safe distance away (about 10 to 12 miles), and as there would be very little chance of the submarine renewing the attack on the convoy in my opinion, I decided to rejoin the convoy, resuming position ahead shortly before 4 o’clock.

Fresh oil was coming to the surface in patches when we left the vicinity, and my opinion is that the submarine must have been severely damaged.

The commander of the escort, in forwarding the above report, stated:

As a result of this experience I have no suggestions to make.

We submit that the action of the escorting vessel as above reported and the tacit approval of the escort commander are not in accordance with sound practice.


The “General estimate of the situation,” which has received the official approval of the Allied Naval Council includes among the measures to be taken in the following:

We must assure ourselves that on every occasion of contact with a submarine the maximum tactical use shall be made of that contact.

The report of the escorting vessels shows that the idea of defense and not offense was uppermost in the minds of both the captain of the vessels and of the escort commander. They left the scene of action when no decision had been reached, and when every indication favored an expectation of destroying the enemy. The incident shows that the officers concerned were not familiar with the accepted policy. We therefore recommend that the following be issued as a doctrine of antisubmarine attack to all hunting vessels and to all zone escort vessels:


The enemy’s submarine campaign can not be defeated by defensive measures alone.

The system of escorting convoys is in part a deployment in readiness, and serves to bring hostile submarines into close tactical contact with a concentrated force of our antisubmarine vessels more frequently than is possible by other means.

It is imperative that full advantage be taken of such contacts to destroy the enemy, to accomplish which the role of escorts of antisubmarine types must instantly be transported from defensive to offensive, and a vigorous counterattack prosecuted. Every submarine destroyed saves about 40,000 tons of shipping per year.

To cover such cases the following is tentatively prescribed as—


1. The maximum possible advantage must be taken of each and every close contact with an enemy submarine to pursue it to destruction. The mission of protecting the convoy becomes secondary to the destruction of the submarine.

2. The pursuit and attack will be made by at least half of the escorting force, and will be continued until no reasonable hope of destroying the submarine or of sighting it again before dark exists. An exception may be made in the case of a troop ship convoy, but the pursuit shall even then invariably be made by one or more of the escort.

3. As a rule every close contact with an enemy submarine shall be construed as an order to attack until not less than three-quarters of all depth charges on the attacking vessels have been expended.


This rule shall not operate to prevent the expenditure of more depth charges if considered necessary. In general, the attack should be as heavy and persistent as possible.

4. If the attacking submarine is not seen, a number of depth charges will nevertheless be dropped at random in the most promising area.

5. In cases where the presence of a submarine is not definitely known, but suspicious indications are sighted, the above rule regarding number of depth charges to be dropped does not apply.

[Extract from Memorandum No. 71, “History of Planning Section.”]

Initiated by the American Planning Section with a view to emphasizing principles brought out in previous papers as well as indoctrinating title antisubmarine forces. The need for further special treatment of this subject would not have been apparent to the Planning Section but for the routine practice of scrutinizing operational reports. The incident points to the necessity of a Planning Section keeping in close touch with operations. The forwarding comment of the Force Commander on 29 May follows:

“2. Memorandum No. 20 was prepared by the Planning Section of my staff after having read a report by an escorting vessel in which it was made plain that the escorting vessel considered that it was unnecessary to insure that it could not attack the convoy. Memorandum No. 20a is a joint memorandum by the Planning Section of my staff and the Plans Division of the Admiralty on the same subject.

“3. The broad idea expressed in both memoranda is that on every occasion of contact with an enemy submarine it should he pursued to destruction if possible, since the enemy’s submarine campaign can not be defeated by merely defending shipping.

“4. The problems and situations presented by the naval warfare that is now being carried on are new to naval experience, but a doctrine is being gradually evolved and it is important that the basis of this doctrine should he the offense rather than the defense.

“5. The 'guiding principles and general instruction’ as appearing on pages 3 and 4 of Memorandum No. 20a are, in general, approved, and will doubtless appear in the final doctrine evolved from current experience. With particular reference to Item VI it may be said that the protection of the convoy may often be best accomplished by a vigorous attack on the threatening enemy. With this fact in mind it is apparent that the initiation of an attack on the submarine is not in fact a subordination of the protective mission to the offensive mission. It is furthermore the fact that certain limited areas, such as the North Channel leading to the Irish Sea, submarines do not operate in pairs or groups but practically always singly, so that there is little danger of the convoy being attacked by any submarine other than the one that is being hunted.”

Memorandum No. 21.

(Not to be published at this time.)


Memorandum No. 22.


10 April, 1918.

(See Map No. 1, “The North Sea.”)


Through the kindness of the Plans Division of the Admiralty arrangement were made with the vice admiral commanding at Dover by which the Planning Section was given an opportunity to visit Dover and to become familiar with the efforts being made by the force under Vice Admiral Sir Roger Keyes, R. N.

We (Planning Section) left London on April 3 for Dover. The following morning we called on Vice Admiral Keyes, who received us very cordially, and immediately said that he was ready and willing to tell us anything we wished to know about the Dover barrage and other activities under his command. He gave us a copy of general orders governing activities in the district, and showed us his “war room,” where a watch is kept night and day by a commissioned officer. There was nothing of particular interest in the war room, except that an hour-to-hour record was maintained of everything that was going on in the district. The methods of keeping this record were by means of charts and movable pins carrying the names of the vessels that were operating. The war room is connected by telephone with Dunkirk, Calais, the Admiralty, and operation points within the district, so that any movements that may be observed can be reported quickly to the war room for plotting and subsequent decision. At night the duty officer is in constant telephonic communication with either Admiral Keyes or his staff commander, so that any situation that may develop during the night can be handled with practically no delay.

Vice Admiral Keyes and Rear Admiral Tyrwhitt (who commands at Harwich) are very warm personal friends, and consequently cooperation between the two stations is of the most thoroughgoing kind.

Operations within the Dover command include the following:

(a) Bombardment of the Belgian coast, and especially of Zeebrugge and Ostend.

(b) Patrol of the mine barrage.

(c) Extension of the mine barrage by the laying of additional mines.


(d) The protection of coastal traffic which comes through the Downs.

(e) The protection of barge traffic from Sandwich across to Calais, Dunkirk, and especially to the Belgian Canals still within allied lines.

(f) The escort of troops from Folkestone and Dover across the Channel.

(g) The patrol of the mine fields by P-boats.

(h) The support of the mine-field patrol by monitors, destroyers, and other light craft.

The Mine Barrage.

The present mine barrage is composed of upward of 14 rows of mines planted at various depths from 25 feet below the surface to a depth sufficient to prevent submarines from successfully diving under the mine barrage. The northern line of mines extends from the vicinity of Cape Gris Nez to a point midway between Dover and Folkestone. The mine field is being thickened and repaired constantly, and extends from coast to coast without any gaps.

As those submarines that have passed the barrage usually go through on the surface, the question at once arises as to why the mine barrage is not carried up to the surface.

There is a rise and fall of tide of from 18 to 20 feet in the Dover Straits. Experience to date has demonstrated that it is impracticable to have a mine exposed on the surface of the water, on account of the action of the sea in causing the mine to come adrift very soon; and also on account of the practical impossibility of replacing mines that do so come adrift.

The practice is to place the mines sufficiently below the surface to insure that they shall continue to watch during a reasonable period of time. The effect of this system is that mines planted 8 to 10 feet below the surface of the water at low water are 28 to 30 feet below the surface at high water. It is known that submarines invariably choose a point near high water to attempt to force the barrage.

Since it has been found impracticable so far to develop a mine or a mine gear that will rise and fall with the tide and watch properly, it has been found necessary to keep the mines sufficiently below the surface of the water at low water to enable the entire barrage to be patrolled in all directions by surface craft without danger to themselves. It would be perfectly practicable to have the mine barrage complete to the surface at low water; but if this were done, it would not be practicable to patrol the barrage at any time by surface craft.

We have learned recently that the Mines Division of the Admiralty were not cognizant of the special problem presented in the mine barrage effort at Dover until two months ago—about the time


that Vice Admiral Keyes took over the command at Dover. Until that time the Mines Division at the Admiralty were under the impression that the Dover Straits were tight, and consequently needed no special mine treatment. They now understand fully that the problem is to produce a mine and mine gear that will watch at a constant distance below the surface of the water, no matter what the state of the tide.

The Planning Section suggests that this problem be considered by the Bureau of Ordnance, with a view to developing, if possible, an American solution. The Planning Section has already indicated this problem to Lieutenant Commander Thompson, and has suggested to him that we get a digest from the Admiralty of all efforts that have so far been made to solve the problem, and the results of each one of these efforts in order that the Bureau of Ordnance in its investigations may not have to go over the same ground that the Admiralty has already covered.

The Bureau of Ordnance, in its study of the problem, should consider that the principal difficulties presented at Dover are—

(а) A strong tidal current.

(b) Rise and fall of tide of about 20 feet.

(c) Poor holding ground.

(d) Heavy seas.

(e) Countermining of mines in the barrage either by explosion due to the attempted passage of submarines or by accidental explosion of mines.

Coastal traffic through the Straits of Dover will not interfere seriously with a surface barrage, since all traffic now is compelled to pass through a barrage gate over a deep mine field.

The necessity of a barrage to the surface is understood and fully appreciated by everyone. The most promising development at present for the mining to the surface is found in the acoustic mine, which we understand is now on a manufacturing basis, experimental work having been practically completed.


The system of local protection of the barrage, and of the effort to compel all submarines attempting to pass the barrage to dive into the mine field, consists in general of two lines of trawlers in position on the edges of the barrage, one to the north and one to the south, supported by P-boats. At night the trawlers burn flares which light up the water in favorable conditions for a couple of miles around, thus making it hazardous for a submarine to attempt to go through on the surface. Between the two lines of trawlers there are drifters, which themselves show no lights, and which maintain themselves


in readiness with 12-pounder guns to attack any submarine which may be seen going through between the trawlers. Both the trawlers and the drifters are at great disadvantage because they are slow and unable to catch a submarine that runs through at its best speed. The difficulties of hitting targets at night from a lively vessel are of course fully understood.

In order to meet this deficiency of speed in the trawlers and drifters the vice admiral at Dover recently has added to his command a considerable number of P-boats, which maintain themselves also in readiness between the lines of trawlers. There are about to be added to this system of protection of the mine field and guarding against the passage of submarines two additional lines of vessels which will be moored in position, one line to the north of the barrage and the other to the south, each fitted with four searchlights, which will be in constant employment when the weather is suitable in searching for enemy submarines.

As the enemy has from time to time made raids on the light craft patrolling the barrage, the necessity for rallying points has developed and is now being solved by monitors, which are suitably spaced on the northern side of the barrage.

In addition there are patrol lines still farther to the northward of the barrage, where strong destroyer forces are kept under way in constant readiness to meet any attack the enemy may make by surface craft in the direction of Ostend.

It has been found that the flares on the trawlers are more effective on cloudy nights, when their light is reflected onto the water by the clouds, than on starlight nights. Trawlers showing flares are themselves unable to see anything.

When submarines are sighted, the light of the flares is augmented for fire-control purposes by star shells and, if possible, by searchlights from the firing ship.

As an indication of the efficiency of the present form of the barrage and patrol effort, the following comparison of vessels (large submarines only) through the Straits of Dover is cited:

Month. Number of boats. Number of passages. Number of passages north about. Number of passages via Dover Straits.
December 21 42 17 19
January 13 26 18 5
February 21 42 39 1

Note.—No large submarines are known to have passed through Dover Straits since 18 February.


During the time of our visit to Dover several destroyers had been loaned to Dover from Harwich on account of the extra strain placed


on the Dover command by the necessity of escorting troops to France. A movement was in progress for reinforcing the British forces in France through Dover and Folkestone, which involved a transfer of about 300,000 troops.


On the first day of our visit Admiral Keyes took us in a torpedo boat to witness the laying of smoke screens by coastal motor boats. A single coastal motor boat, using sulphonic gas in its cylinders, was able to lay a very dense white screen that remained effective for a considerable time.

Admiral Keyes told us that recently a small coastal motor boat, well to the northward of the barrage, had been aide to engage a little after dawn an enemy destroyer and by firing its torpedo blow the stern off the destroyer, and then by maneuvering behind its own smoke screen had escaped the pursuit of other enemy vessels in the vicinity. The captain of the motor boat received the D. S. O. for his exploit.


On the second night of our visit two officers, Captains Knox and Yarnell, went onto the monitor Sir John Moore, which was stationed in support of and close to the barrage through the night. On the same night Captain Schofield went in a destroyer leader, Whirlwind, on the central patrol to the northward of the barrage; in these ways we were able to get in touch with some of the difficulties that attend operations in the Straits.

The principal difficulty of the patrol and support is due to the frequency of thick weather. Whenever a fog sets in light craft become very quickly scattered; long experience has demonstrated that the best procedure is to get to an anchorage and remain in readiness to resume station immediately the fog lifts sufficiently to permit safe navigation. It appears that the tides in the Straits of Dover are not dependable, being subject to considerable fluctuations, owing to weather which may not be felt in the Straits.

In addition to the support that is constantly under way to the northward of the barrage, there are other supports anchored in or near the Downs in readiness to attack any submarine which may hazard a passage through the shallow waters of the Downs. The great danger to submarines in shallow waters has resulted in making the Downs practically a safe passage; but notwithstanding this safety the usual precautions are taken to guard anything which may be in the Downs.


The last instance of the bombardment of Dover by an enemy submarine was an effort on the part of the submarine to trap destroyers


which were supposed to be lying inside. The submarine first approached Dover and laid a mine field off the entrance to the harbor, then withdrew to a slight distance and fired into Dover. As a matter of fact, its aim was bad and no shells landed within the city limits, but in the outskirts. British destroyers outside heard the fire, came promptly to the rescue, and compelled the submarine to dive. The mines were discovered and swept up before they had done any damage.

In the case of the loss of several drifters and trawlers in January considerable blame was attached to officers on duty that night, both in the support and in the patrol. The trawlers and drifters behaved with a good deal of spirit. The escape of the enemy destroyers was due largely to the assumption that the failure of the enemy to make the proper recognition signals did not necessarily indicate them to be enemy vessels, and to the fact that the vessels attacked had no radio. Further, the engagement with the trawlers did not become known to other parts of the line until it was too late to interpose in force between the enemy and its home port. The general mix up resulted in two or three court-martials and in the loss of his command by an officer who has two submarines to his personal credit and the D. S. O. with bar.


We visited the air station at Dover, where two of our naval airmen are now acting as pilots of British airships. Conversation with the British and American airmen (who were all pilots of lighter-than-air craft) did not cause us to change in any way our conclusions as to the relative usefulness of lighter and heavier than air craft in the present war.


On April 6 we called on Admiral Keyes at his residence to say good-by and found him out. We left messages of thanks with the chief of staff, Commodore Boyle, and then went to the railway station. Just previous to the departure of the train Vice Admiral Keyes and his flag lieutenant appeared on the platform to say good-by. The railway station was some 2 miles from Admiral Keyes’s office, and we were very much pleased with his courtesy in seeing us off in this way.

Throughout our visit there was the utmost cordiality on the part of all British officers with whom we came in contact. We were particularly impressed with the loyalty and affection felt for Vice Admiral Keyes by all those portions of his command which we visited. Our personal impression was Vice Admiral Keyes was a man of such high caliber and character that he would undoubtedly rise some day to the highest command possible in the British Navy.


Memorandum No. 23.


23 April, 1918.


The following are questions asked of the Planning Section by the Force Commander and the Planning Section’s replies thereto:

Question 1. As all nations since time out of mind have put the officers of their armies and navies in uniform instead of in citizen’s clothes, it may be assumed that in the opinion of the world the reasons for doing so are considered sound. What are these reasons?

Answer. (a) Uniforms give a feeling of unity and strength among military or naval forces that can not be obtained in any other way.

(b) Uniforms simplify the clothing of military forces.

(c) Uniforms are necessary for the easy recognition of friend and enemy.

(d) Uniforms elevate morale.

Question 2. In all services officers are provided with certain uniforms that are embellished b