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Admiral Henry T. Mayo, Commander-in-Chief, Atlantic Fleet, to Secretary of the Navy Josephus Daniels


File.                     10 August 1918.

From:     Commander in Chief

To:       Secretary of the Navy (OPERATIONS)

SUBJECT:  An Estimate of the Naval Situation in the Atlantic Ocean.1

References:    (a) C-in-C Secret File 211, 2 February, 1918,

subject “Estimate of the Situation with regard to the efficient development of the operations of the ATLANTIC FLEET”.

(b)  C-in_C Secret File, 12 April, 1918, subject

- “Development and operations of BATTLESHIP FORCES of the ATLANTIC FLEET.”2



     1.   The adopted mission of the ATLANTIC FLEET is:

 “(1) To guard all troop and mercantile trans-Atlantic convoys against German or Austrian raiders of any type or strength.

(2)  To support the British GRAND FLEET against any attempt of the German HIGH SEA FLEET to gain temporary control of the English Channel.


2.  The naval forces at the disposal of the enemy mage be considered limited to those of Germany as the Austrian forces should be contained by the combined fleets of Italy and France.

     3.  These forces are organized in two main forces:-

          (a) The HIGH SEA FLEET

(b) The submarine forces engaged in attacks on Merchant shipping and transports.


     4.   The German HIGH SEA FLEET is inferior to the reinforced British GRAND FLEET to the extent of about one half. This inferiority precludes much danger of an attack by the HIGH SEA FLEET under normal conditions. It is therefore, necessary to consider what developments could be made that might be considered to put the HIGH SEA FLEET in condition to warrant such an engagement.

     5.   The only developments in naval warfare which might be considered to offset the superiority of the GRAND FLEET, which are known, are poison gas and the torpedo plane. There is little doubt but that the next naval engagement in which the HIGH SEA FLEET takes part will find the employment of these weapons.

     6.   The possibility of the German HIGH SEA FLEET using these weapons, and the conditions under which an engagement with the British Grand FLEET might be sought, have been discussed at some length in reference (b). In this previous estimate the conclusion was reached that the German HIGH SEA FLEET might seek an engagement with the British GRAND FLEET in the vicinity of the German bases at Zeebrugge and Ostend. Mine fields so placed as to let in the path of the GRAND FLEET in a southward movement have been located.

     7.   A campaign of this nature, in conjunction with naval raids in the Channel, or a military raid on the coast of England, might if made in conjunction with a strong military offensive against the northern part of the battle line of the western front, assume a very threatening nature, and if even partially successful could be used to bolster up the morale of the Teutonic peoples during the coming winter.

     8.   In view of the possibility of such a campaign, the Commander-in-Chief, in reference (b), recommended that all United States super-dreadnaughts should be sent to European Waters to support the British GRAND FLEET.

     9.   That such a campaign has not yet taken place indicates that the above conclusion was wrong; or, that the enemy is not yet prepared for such an attack; or, that some more promising plan (from his point of view) is being developed. The logical time for such a campaign is in co-operation with a strong military offensive against the another part of the western front, and it cannot be considered that such an opportunity will be overlooked.

     10.  The fact that his campaign has not yet taken place does not change the previous decision that all United States super-dreadnaughts should be based in European Waters for the support of the British GRAND FLEET, but the development of the cruiser submarine; the lateness of the season of the year, and the improbability of a successful military offensive by the German armies on the western front during the remainder of the season favorable to military operations, may be found to modify the decision to some extent.


     11.  The unfavorable turn of the military situation, from the German point of view, will probably prevent a successful military offensive against the northern part of the western front during the remainder of this year. The results of an attempt by the German HIGH SEA FLEET could hardly be such as to insure German control of the sea against the remaining naval forces of the Allies. Such a campaign could not be justified except in conjunction with a strong military offensive, in which case interference with cross channel transportation, which might accrue from temporary control of the Channel, might offer adequate returns. It may be reasonably concluded that no such campaign will be attempted, although the possibility of such a campaign must not be lost sight of, and the disposition of the United States forces, super-dreadnaughts and destroyers suitable for a major fleet action, must be such as to offer a change to support the British GRAND FLEET in case of such a campaign, and to prevent the German Navy from gaining even a temporary control of the English Channel.


     12.  The results of the enemy submarine campaign against commerce and transports have undoubtedly been disappointing to them, and with the increase in the anti-submarine craft, and more efficient weapons for use against submarine, it is practically assured that the result of the war can no longer be considered to depend upon losses by submarine operations.

     13.  The tonnage available for the transportation of troops is, however, not much greater than absolutely necessary for the prosecution of the war, and a large part of the building program of both the United States and the Allies, is composed of vessels which will not be suitable for troop transportation.

     14.  Anti-submarine operations cannot therefore be relazed, but must be pressed with greater vigor due to the increased area in which this type of craft is now operating.

     15. The development of the cruiser submarine has so increased the area of the submarine operations that destroyer escort for troops convoys throughout the entire trans-Atlantic voyage is desirable. Destroyer escort for merchant convoys throughout the entire voyage is also desirable but on account of the number of destroyers required, not, as yet, practicable.


     16.  Although the efficiency of the enemy’s submarine campaign is decreasing, and the construction of new tonnage is such as to practically insure adequate available tonnage for the transportation of supplies to the allied armies and nations, the tonnage available for transport of troops is no greater than that required for success.

     17.  The development of the cruiser submarine has greatly increased the area in which vessels are subject to submarine attack.

     18.  Successful operations against transports carrying United States troops will be especially valuable to the enemy in raising his morale.

     19.  Every endeavor should be exerted to prevent successful submarine operations by the enemy, but in view of the greater moral effect of successful operations against our transports, the greatest stress should be placed upon the protection of all troop convoys.


     20.  Outside of the two types of operations which have been discussed above, there appears to be but on other general type of operations which might offer success; namely – Extensive Raiding operations against transports and merchant ships, using surface craft alone or in combination with submarine craft.

     21.  Considering first operations surface craft alone, we may say that there are four types of vessels to be considered:

(a)    Converted merchant shipping,

(b)    Light or protected cruisers,

(c)    Major ships,

(d)    Destroyers.

     22.  (a) Converted merchant shipping – This type has, except in the North Sea, been the only type of raider employed since the destruction of the German light cruisers so employed in the early part of the war. The advantage of this type lies in their harmless appearance and in the possibility of disguise. The disadvantage lies in their low speed and inferior fighting power.

     23.  Converted merchant shipping may be employed but the fighting power of such craft would not be sufficient to overcome the usual ocean escort, and consequently are not to be feared as a decisive factor.

     24.  (b) Light and protected cruisers – Vessels of these types have a real value in major action with the fleet and the use of such ships as raiders would indicate that an attempt to fight a major action with the British GRAND FLEET had been abandoned. These types have the advantage of speed and fighting power, as compared to merchant raiders, but are without the latter’s advantage of disguise. The fighting power of these vessels is inadequate to the destruction of the average ocean escort, and their fuel capacity is not sufficient to give them a great radius of action.

     25.  Vessels of these types would experience more difficulty in gaining the sea than would merchant shipping, because their character would at once become evident. They have insufficient fighting strength to force their way through the light forces that might be encountered. Their one advantage is speed. Because of their inferior power, however, attacks by either of these types cannot in all probability, result in such serious losses as to affect the successful issue of the war.

     26   (c) Major ships – In this class are included battleships and battle cruisers. Vessels of either of these types would experience considerable difficulty in getting to sea unobserved, but due to their strength would be able to fight their way through the observation forces. After gaining the sea they would be difficult to locate and due to their strength as compared to most ocean escorts would be able to attack advantageously, any convoys of merchant ships or transport that might be encountered, unless the ocean escort is greatly strengthened.

     27.  The great disadvantage in the use of this type for raiding is the danger that they will be cut off from their bases and be sunk by superior forces, or that they will become derelict through the exhaustion of their fuel. The disaster which might be brought upon a convoy of troops ships by an encounter with a vessel of this type, and the great influence upon the morale that a successful operation of this nature might have upon the Teutonic peoples, make the consideration of this type of operation most necessary.

     28.  The great superiority of the Allies in major ships cannot be employed more advantageously than by assuring the safety of transports carrying United States troops to France.

     29.  (d) Destroyers -  This type have not been used in raiding expeditions except in the North Sea. The limited radius of action and the inferior fighting capacity of the German Destroyer compared to the modern British or United States destroyer, will probably prevent their use in the Atlantic, though raids in the Channel are possible. Such raids in the Channel could in all probability be successfully countered by the British without assistance from our destroyers.


     30. The development of the cruiser submarine affords the enemy a type of vessel particularly adapted to scouting operations. If submarines do not attack their presence can not be readily detected and, although their radio could be heard, it would be difficult to keep such a vessel from tracking a convoy, particularly before the destroyers joined the escort.

     31. Additional smaller submarines previously directed to the positions in which the battle cruiser expected to fuel, would operate as a scouting force during such time as fueling was in progress.

     32. This combine operation has many advantages and appears to be the most logical procedure, provided the battle cruisers can get to sea.


     33. The possibility of successful operations against convoys of troop ships appears to be the principal menace to the successful prosecution of the war by the Allies and every available vessel that can be successfully employed to insure their safety should be so employed.

     34. The possible operations of the German Navy against which the United States Navy must prepare are:

(1) Submarine operations against transports and merchant shipping.

II. Raiding operations by all types of surface craft but primarily by major ships, or converted merchant ships.

III. An attempt of the German High Sea Fleet to gain temporary control of the English Channel with a view to forcing the British GRAND FLEET to fight a decisive action at a point selected by the Germans.


 35. The distribution of the forces of the ATLANTIC FLEET at present is based upon a general plan which, to some extent, has been governed by a consideration of all types of possible operations of the enemy considered in the preceding paragraph. Such re-consideration as is deemed necessary is due to the changed conditions which were enumerated in the consideration of the general situation from which the present mission of the ATLANTIC FLEET was adopted.

 36. The present policy with regard to the anti-submarine forces of the ATLANTIC FLEET IS SATISFACTORY, and the disposition of these forces appears to be efficient. No change in policy or disposition of these forces is recommended, except that in view of the greater danger from raiders, or from a temporary control of the English Channel by the German HIGH SEA FLEET, it should be constantly kept in mind, that when and where necessary, destroyers should be withdrawn from anti-submarine escort to engage in anti-raider or major fleet operations.

 37. The British GRAND FLEET has been reinforced by BATTLESHIP DIVISION NINE. Such reinforcement is considered insufficient in case the German HIGH SEA FLEET should be able to bring the GRAND FLEET to action in a position, and at a place, chosen by the Germans, if, as is anticipated in case of a major action the Germans will be equipped with poison gas and torpedo planes.

 38. Further reinforcement of the British GRAND FLEET is considered desirable, but in view of the danger of raiders passing out of the English Channel a strategic concentration may be deemed sufficient. The disposition of the remained dreadnaughts of the UNITED STATES ATLANTIC FLEET should there be such as to insure the maximum protection against the raiders while maintain a strategic concentration with the British GRAND FLEET.

 39. The remain[i]ng forces of the ATLANTIC FLEET may be enumerated as follows:


(b)    Battleships of BATTLESHIP FORCE ONE (Including DIV. FIVE.)


 40. All of these vessels should be used in such manner as to afford the greatest protection to convoys of troops ships and merchant ships.

 41. The changes in disposition of forces should therefore be based upon the following decisions:

(a)    All super-dreadnaughts are to be based where they will be a strategically concentrated with the British GRAND FLEET in the event of a major action near the eastern entrance to the English Channel.

(b)    The DELAWARE and NORTH DAKOTA to be based with the super-dreadnaughts or elsewhere as may appear desirable.

(c)    The pre-dreadnaught battleships to be based and operated in the manner most efficient for the protection of trans-Atlantic convoys, against surface raiders.

(d)    The CRUISER FORCE to be based and operated in the manner most efficient for the protection of trans-Atlantic convoys against surface raiders.


 42. The probable locality of a major engagement is considered to be the vicinity of the German bases at Zeebrugge and Ostend. Action in this vicinity could be forced upon the British GRAND FLEET by a naval raid in the Channel or by a military raid on the coast of England, in the vicinity of London.

 43. In the following consideration of bases, Kentish Knock has been considered as the probable locality of such a major fleet action.

 44. The distance from Kentish Knock to Rosyth is about 390 miles. To be strategically concentrated with the British GRAND FLEET, the base of the United States super-dreadnaughts must be within this distance of Kentish Knock.

 45. Within 390 miles of Kentish Knock there are not suitable bases except the channel ports, and Brest. The channel ports of both Great Britain and France are overcrowded now and the basing of a squadron of dreadnaughts on any of these ports would probably seriously interfere with cross channel traffic. The Brest Roads are 360 miles from Kentish Knock and from all data at hand appear to offer a satisfactory base.

 46. In case the British GRA<N>D FLEET is based at Scapa the distance of our base from Kentish Knock can be increased without destroying the strategic concentration. This increase in distance furnishes no additional bases for consideration except Berehaven. Berehaven lacks many advantages of Brest as regards questions of communication, supply, and fuel, and in the event of operations against battle cruiser raiders in the channel is no<t> so well situated as Brest.

 47. In the further consideration of a plan for the accomplishment of the mission of the fleet it will be assumed that the super-dreadnaughts are to base on Brest.


 48. Provisions adequate for the protection of our transports against operations by the battle cruisers should be sufficient to afford protection against surface raiders of other types.


 49. The enemy may use any types of surface craft as raiders.If however, battleships or battle cruisers are based used the number will probably not be large, whereas if merchant cruisers or light cruisers are used it is quite probable that the number of raiders out at once will be as large as they may deem advisable.

 50. All enemy vessels of types suitable for use as raiders are based on the home coast of Germany.

 51. There are two avenues of escape to the Atlantic Ocean from the North Sea:

(a)    Round the north of Scotland.

(b)    Through the English Channel.

 52. (a) has the advantages of

(1)    More sea room.

(2)    Avoids British torpedo craft bases,

(3)    Norwegian territorial waters can be used to Assist in avoiding mines.

(4)    Longer period of darkness in each day,

(5)    More chance of evasion.

     (a) has the [dis]advantages of :-

(1)    Leading nearer to main bases of British GRAND FLEET,

(2)    Being furtherest from the probable convoy routes,

(3)    Being the obvious way.

 53. (b) has the advantages of-

(1)    Surface craft of equal power will not be met unless the United States dreadnaughts are based in the vicinity of the English Channel,

(2)    Nearest way to the transport routes,

(3)    Least obvious way,

     (b) has the disadvantages of –

(1)    Greater danger form mines,

Greater danger from torpedo crafts,

More likelihood of being sighted,

Fewer hours of darkness.

 54. There does not seem to be much choice between the two routes. The greatest danger in a passage of the English Channel, is the danger from mines. Undoubtedly the German vessels are fitted with paravanes and in addition to those, high speed sweeps carried by destroyers would undoubtedly be used to sweep up the mines. The battle cruiser would no doubt be screened also by a strong screen of destroyers and light cruisers in sufficient strength to fight off any British forces of light vessels based in the vicinity of the Channel.

 55. In case of an attempt to pass north about, the battle cruisers will attempt to take full advantage of darkness and fog. It is quite possible that the German HIGH SEA FLEET might make a demonstration in the vicinity of the British coast in order to draw the British battle cruisers and destroyers away from the northern area during the passage of the battle cruiser.

 56. In view of the probability that the first attempt of this nature will be the most successful, it is quite within the probabilities that attemp<t>s to pass out by both routes may be made simultaneously.

 57. The German HIGH SEA FLEET may be expected to make demonstrations against the British Coast during the period that the battle cruisers are out, in order to prevent the detachment of British battle cruisers to participate in anti-raider operations.

 59. As a force of at least six battle cruisers would be required to have a chance of success in running down the enemy battle cruiser, it is extrem[e]ly doubtful if the British GRAND FLEET would be willing to sacrifice that strength to hunting raiders.

 59. The cruising radius of the latest German battle cruisers is sufficient to permit them to reach the West Indies at a speed of 20 knots after steaming 24 hours at 25 knots during their escape. They would still have about 15% of their fuel capacity remaining.

 60. The problem of logistics would be a most serious one with them and the logical course appears to be <to> fit to out one or more of their large merchant ships to act as tender and collier.

 61. There are available for this:

          (a) The IMPERATOR – 52000 tons  25 knots speed

          (b) The COLUMBUS  40000 tons  21 1/2 knots speed

and possibly

          (c) The HINDENBURG- 40000 tons  21 1/2 knots speed-

which vessel was building in 1916.


 62. Our forces would consist of:

(a) Eight super-dreadnaughts, based on Brest.


(c) Two MICHIGAN type, 6 MINNESOTA type.

(d) Five GEORGIA type.

(e) Seven armored cruisers.


    assigned to training and coast defense.3

 63. There are two courses of action:

(a) Strictly defensive,

(b) Offensive defensive.

 64. Course (a) is by far the simplest and would consist in supporting the ocean escorts by dreadnaughts whenever it is considered that an enemy battle cruiser may be out.

     This course would lead eventually to a permanent escort of dreadnaughts for all convoys of troop ships, but would not prevent the destruction of a perhaps vital amount of shipping not under such escort. It would permit the freedom of the sea to the enemy battle cruiser.

 65. Course (b) would be to operate defensively with regard to the one or two troop convoys nearest Europe and offensively with the remaining dreadnaughts and such destroyers and other vessels as might be available, to run down this raider. It is quite true that the battleships cannot over take a battle cruiser, but constant pursuit would prevent the battle cruisers stopping to fuel and consequently soon exhaust her fuel supply.

 66. In case of a passage through the Channel, the dreadnaughts and such destroyers as might be available should be able to intercept and defeat or drive back the battle curiser before she cleared the Western end of the Channel.

 67. A battle cruiser gaining the sea north about will be more difficult to locate and scouts and destroyers will be required to assist the dreadnaughts.

 68. The vessels of our Navy most suitable for this are the armored cruisers. It is recognized that they are of inferior speed and power to a battle cruiser, but such a vessel on a raiding expedition would not desire to exp<e>nd fuel in chasing down scouts. She would not know into what she was being led and would be wary about following a scout.

 69. By substituting the SOUTH CAROLINA and MICHIGAN and six MINNESOTA type for the armored cruisers as ocean escorts, these cruisers can be made available for scouting and, if necessary, relieving the ocean escorts on the eastern end of the voyage.

 70. The NORTH DAKOTA and DELAWARE could be based on Halifax or Guantanamo or on the home coast. Their primary duty being to guard the western Atlantic against battle cruiser operations against the coast and to prevent such vessels from fueling in the western Atlantic if they are tracked to this vicinity.

 71. The five GEORGIA type would assist the NORTH DAKOTA and DELAWARE in defense of the coast. The radius of action of these vessels is probably insufficient to permit their efficient use as ocean escorts.


 72. (1) To assign to the Commander-in-Chief ATLANTIC FLEET the mission of guarding all trans-Atlantic convoys against raiders.

     (2) To base the super-dreadnaughts PENNSYLVANIA, ARIZONA, UTAH, OKLAHOMA, NEVADA, (MISSISSIPPI, NEW MEXICO, and IDAHO when ready) at Brest

     (3) To base the seven armored cruisers at Berehaven as scouts and eastern ocean escorts.

     (4) To base NORTH DAKOTA and DELAWARE on home coast, Halifax or Guantanamo, as detail plans may indicate best.

     (5) To use SOUTH CAROLINA, MICHIGAN and 6 MINNESOTA type as ocean escorts and troop convoys.

     (6) To base five GEORGIA type on home coast.

     (7) The Commander-in-Chief to assume direct control over offensive anti-raider operations.

     (8) To base SQUADRON ONE and DIVISION “A” on home coast and operate them as training unites.

H. T. Mayo         

Source Note: DTS, DNA, RG 45, Entry 517B.

Footnote 1: See also: Mayo to Daniels, 10 August 1918.

Footnote 2: Neither of these documents has been found.

Footnote 3: For the make-up of the different classes of battleships listed here, see: ibid.

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