Rear Admiral Charles J. Badger, Senior Member, General Board of the United States Navy, to Secretary of the Navy Josephus Daniels
DEPARTMENT OF THE NAVY
(Serial No. 820)
FEB 26 1918
From: Senior Member:
To: Secretary of the Navy.
SUBJECT: The control of the air in the Dunkerque-Calais region to prevent the passage of Dover Strait by German submarines.
1. The latest and most reliable information obtainable by the General Board indicates that of the German submarines based at Ostend, Bruges and Zeebrugge, practically all pass through Dover Strait to carry on their operations in the English Channel and off the French coast. Such information further indicates that the efforts of the British to close the Strait promise only partial success in the future; and that scouting for submarines in the English Channel and off the French coast, because of the inadequate number of destroyers and other surface patrol craft, is now practically without result.
2. The outlook for new destroyer construction in the United States for the next six months is not encouraging. The report of the Bureau of Construction and Repair of the vessels under construction, United States Navy, dated February 11, 1918, makes the following showing:
Probable dates of completion.
First half of 1918 ----------- 24 destroyers
Second half of 1918 ---------- 109 destroyers
First half of 1919 ----------- 98 destroyers
Second half of 1919 ---------- 30 destroyers
In 1920 ---------------------- 2 destroyers
and 9 destroyers with no dates fixed for probable completion.
3. After the probable dates of completion given, it is a reasonable estimate that at least two months will be required to fit out, man and get into service in European waters the destroyers enumerated in the table. Consequently, it will be September, 1918, before the 24 destroyers to be completed in the first half of 1918 actually get to work against submarines.
4. In the meantime, the destroyers now in service in British and French waters have had a year and a half of arduous cruising under exceptionally trying conditions for the upkeep of material. Many of them undoubtedly will have to be extensively overhauled by September. So the outlook for an increase in present destroyer force, which the Commander of U.S. forces abroad states is inadequate to successfully combat the submarine menace, is by no means encouraging unless more energy is devoted to destroyer production than seems now probable or possible.
5. Granting a fair measure of success to listening devices, which are still in an experimental stage, and that the British with some assistance from us may develop a better patrol of submarine vessels, the activity of German submarines and air craft makes it imperative for us to develop to the limit an air offensive against the submarine, especially as this form of offensive, in view of the peculiar conditions under which submarines must navigate between German bases and Dover Strait, promises a fair degree of success. In this connection, it is apparent that unless Dover Strait can be closed to submarines, the proposed North Sea barrier will lose much of its effectiveness.
6. The General Board has had the direct testimony of officers who have recently returned from abroad, as to the availability of the Dunkerque-Calais region as a base for seaplane operations against German submarines from Ostend, Bruges and Zeebrugge, and has been much impressed by their arguments and by a careful study of the subject.
7. Captain A.A. Cunningham, U.S.M.C., whose statements were corroborated by Lieutenant Commander J.H. Towers, U.S. Navy, and Lieutenant Commander Kenneth Whiting, U.S. Navy, in his hearings before the General Board, said in part:-
“This place (Dunkerque) appears to offer the best possible opportunity for naval aviation to assist in curbing the submarines; and the reason for this is that the big German submarine bases at Ostend, Zeebrugge and Bruges are very active and are full of submarines. I saw a picture of the base at Bruges, taken during a daylight raid, and in it I saw ten submarine shelters, all undoubtedly full of submarines. Besides this, there were seventeen large seagoing submarines and ten destroyers, unprotected from above, in the basin.
“x x x Dunkerque itself is very congested and is not a very good place for a seaplane station, but was chosen, so far as I could find out, because there is no better location in the vicinity. The buildings of our station are herded together in too small a space. Dunkerque is so near the German air bases that they bomb it every night the weather is satisfactory. They destroyed the large base the British had at St. Pol. The British decided to abandon their seaplane base and are moving it away. The space occupied by their seaplane base might be secured so that our buildings could be scattered over a larger space and minimize the effects of air raids.
“x x x The British apparently are not going to attempt to operate with air craft against submarines in the contested waters on a large enough scale to succeed. They seem to have decided that they can do more damage with the limited number of machines available if they concentrate on bombing the bases. I think if our Navy takes up the problem of controlling the air off the coast of Belgium and sinking the enemy submarines that have to navigate these waters on the surface in a great many places, that the British will be pleased and will assist wherever possible.”
Lieutenant Commander Towers, U.S. Navy, said:-
“The situation in Dunkerque is about as follows: The Germans, according to all the information we are getting, are using the restricted channels along that coast for passing submarines out into the English Channel and further on to the French coast. They have concentrated there a sufficient aerial force to be able to keep the air clear of the allied aircraft in order that this passage will not be hampered. The reports indicate that whenever the French and English have made a determined effort to concentrate a force to control the air, that the Germans, realizing the importance of the matter, have brought up fighting squadrons from other places and have continued to bring them up in sufficient quantities to overwhelm the allied aircraft. As the matter now stands, the allied aircraft don’t dare to go out very far from their base because they have not been able to get sufficient force to combat the Germans. It seems to me, since we have started in at Dunkerque and thereby indicated that we intend to operate against submarines there, and it is conceded to be the best point, we should make every effort to completely control the air. No matter how many bombing machines we put out if there are no fighting machines there to protect them it is a useless sacrifice. I am thoroughly in accord with Captain Cunningham’s views.”
8. From the statements of these officers it appears that submarines coming from Zeebrugge, Ostend and Bruges, bound through Dover Strait, have to navigate on the surface through narrow channels for a distance of about twelve miles; and that the waters between Dunkerque and Dover make it necessary for a submarine if running submerged to come to the surface frequently to avoid the numerous shoals and other navigation difficulties. Because of these difficulties submarines cannot well run at night in this locality. Bombing air craft have proved their efficiency against submarines; and in a restricted area where the submarines must run on the surface, the importance of their use from a nearby base is evident. It is stated that a submarine in motion in good weather, breaking the surface with the periscope, may be seen five miles from an aeroplane.
9. So far, the use of air craft based at Dunkerque has not been attended with the success which the excellence of the weapon justifies because the Germans control the air. Air craft from Dunkerque have to patrol constantly in daylight over the Channel, not knowing when submarines are coming from, or going to, German bases in the vicinity. This the Germans do know positively; and this knowledge enables them to build a seaplane with a shorter radius of action and consequently with a better performance. These bombing planes, with battle planes above and behind, follow the submarine and keep the air clear of the bombing planes from Dunkerque which seek to operate. The Germans habitually cover their bombing planes and convoy their submarines by sending out a number of their best land fighting squadrons. Planes sent out by the British, not adequately protected by fighting planes, have all been shot down.
10. The control of the air is therefore essential in the Dunkerque-Calais region if success is to attend our efforts to close Dover Strait to submarines operating from German bases by the use of air craft. The air craft bases may be at Dunkerque, Calais, or scattered between the two cities, wherever the terrain and over water conditions offer the best locations for land and seaplane work. Dunkerque is only twenty miles from Calais; and it is understood that near Calais there is a lake being investigated which promises well for seaplane performance.
11. That there are very real difficulties to be encountered in wresting the air control from the Germans is evident from the following table of distances of German air craft bases from Dunkerque:
Dunkerque – Courtrai ------ 45 miles
″ - Ostend -------- 20 ″
″ - Zeebrugge ----- 35 ″
″ - Bruges -------- 40 ″
″ - Rouliers ------ 35 ″
″ - Lille --------- 42 ″
And 36 miles of the German battlefront, with its air craft equipment, is within 80 miles (one hour’s flight) of Dunkerque.
On the other hand, control of the air in the Dunkerque region would undoubtedly seriously interfere with, if it did not entirely prevent, the German submarine traffic through Dover Strait. Also, and this is most important, German submarine or air craft bases at Zeebrugge, Ostend and Bruges, and other bases within air craft radius, would be open to extensive bombardment from the air.
12. As to the aircraft necessary for the purpose – The British have made the mistake of trying to operate from Dunkerque – and we are following their example – with bombing seaplanes only. In the presence of German fighting squadrons of land machines, this is futile. There must be, in addition to the number of bombing planes necessary to maintain an efficient patrol over the reaches of the Channel where submarines must come to the surface, a number of the best type of fighting plane of the land type to cover and protect the bombing planes against German counter attacks.
13. Captain Cunningham states that at least thirty bombing seaplanes would be required for the patrol; and that control of the air, at a rough estimate, would take at least 200 fighting machines of the land type. These machines would work together, the land fighting machines covering and protecting the bombing machines in their work over the water. The whole operation is distinctly naval, and should be under naval control, - the Navy and Marine Corps supplying the necessary personnel; the Navy the bombing machines; and the Army, the land fighting machines, - in the same manner that the Navy Department has supplied seaplanes to the Army for service in the Canal Zone and elsewhere.
14. The General Board understands that:- Twenty-five of the 30 bombing seaplanes with the necessary naval personnel according to the latest estimate of production will be available in May, 1918.
The Marine Corps has now ready trained personnel for two squadrons of 16 fighting machines, land type.
The Marine Corps has now the partially trained personnel for two additional squadrons, and that by May the Marine Corps is prepared to put in the field the trained personnel complete for four squadrons – about 600 men.
It is estimated that the Navy and Marine Crops can train and provide the additional personnel to bring the number of fighting squadrons to 12 as rapidly as the planes can be supplied by the Army.
15. The General Board invites the serious attention of the Department to the necessity of getting control of the air in the Dunkerque-Calais region for the objects above discussed, and further considers that these objects are of such importance as to require priority in air craft assignment of personnel and material to accomplish them. And that every effort should be made to obtain the necessary fighting plane of the land type from the Army.
With these objects in view, the General Board makes the following recommendations:-
(a) Select sites for land and seaplane bases in the Dunkerque-Calais region, for the personnel and material required to operate at least 30 seaplanes and 200 fighting planes of the land type, and proceed with the installations.
(b) Use every effort, beginning now, to get the material and train the personnel, and push the installation work, with the determination to get control of the air in this region in the shortest practicable time.
(c) As the Navy and the Marine Corps will have ready by May the personnel for 30 bombing seaplanes, and four squadrons of fighting planes of 15 planes each, proceed with the installations with a view to having them in efficient operation in May.
(d) Obtain from the Army, or by independent contract if the Army will not cooperate at this time 64 or more fighting machines of the land type.
(e) Arrange further to increase the installations as quickly as possible to 200 or more fighting machines, as may be necessary; and provide systematically for additional machines and personnel to make up for casualties.
(f) In so far as the Navy is concerned, and in so far as the Army will cooperate, give priority in material and personnel to the aircraft campaign in the Dunkerque-Calais region, as being of greater importance in the results to be obtained than any other airplane work abroad and at home now projected by the Navy.
(g) Invite the earnest cooperation of the British and French, especially in the provision of fighting machines of the land type, in order that there may be no delay in the efficient operation of the stations. Such cooperation is necessary now because the Army may not be able to supply the required number of fighting machines, and it may take time for the Navy to get them independently.
(h) Proceed with the equipment of these stations now, with the idea that there cannot be too many bombing and fighting planes supplied quickly. The greater the number provided, the sooner control of the air will be obtained, followed immediately by effective interference with German submarine operations through the Dover Strait, and with the operations from German aircraft bases.
<W. S. Benson.>