Admiral William S. Benson, Chief of Naval Operations, to Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters
C O P Y
27 May <26,> 1918. 9:40 p.m.
Opnav 6489 Your 8151 7551 and preceding cables.
First Policy. The Department’s attitude is that the mine barrage, when properly placed and adequately guarded by patrol boats, support, and sufficiently friendly submarines promises to be one of the cheapest and most effective methods of combatting hostile submarines.
Second, Plans prepared by your 3561. The Department is willing to assume the responsibility of providing enough mines to form the barrage in question or another equally long and believe this phase of the question can be arranged without interference with our part of the North Sea barrage plans. The providing of mines is, however, a small part of this problem, which involves additional mine planters,water patrol, and support after the barrage is laid beside requiring quite extensive land operation and military support at the Eastern end of the mine barrage proposed. You will note in our 3734 and 4486 and your 6077 and 6723 that the Department asks for opinion of the Supreme War Council to this particular project and that their opinion is to the effect that no military force should be diverted to this particular operation for the present. In this opinion the Department concurs, but believes that steps should be taken now to prepare for the execution of this or a similar operation as soon as the question of adequate supplies of men and food to the forces on the Western front. The Department can provide the mines for the Adriatic Sea project but estimates it will require the services of 8 additional ships if this project is carried on the same time as the North Sea barrage. This cannot be easily met as there are hardly any ships left in the United States coastwise trade fitted to convert to this work, and to build 8 mine laying ships now will take too long besides interfering with the merchant tonnage project. Therefore, unless Italy, or some of the Allies, can turn over fast ships to which can be utilised for mine laying, the problem of our handling all the mines involved in the plans of your 3561, and at the same time carry on our part in the north sea plan, is fairly serious. From the ten<o>r of your 7551 it is presupposed that the matter of water patrol and support for barrage will be furnished by the Allied forces now in the Mediterranean Sea, and that when the time for Military operations to put this plan into effect is ripe, that said Military forces will be furnished by Italy France or possibly Great Britain. If this view is not correct very definite statement should be made now as to how these two phases of the problem should be handled in order that we may take them under advisement conjointly with the part suggested for us by your 7551.
Third, General strategy of the Adriatic Sea barrage plans. Without approval or disapproval of the present suggested plan in its entirety but merely to bring forward the particular United States interest in the matter the following points are offered. If the Wester n Mediterranean Sea were made safe by barrage from Sicily to Cape Bon, and the Straits of
the M Messina control were made scheme practicable the Eastern Mediterranean Sea situation would be no worse than it is at present, while the liability of the United States to transport both men and supplies particularly to French and Italian Western Mediterranean ports would be greatly facilitated. The length of convoys would be shortened, the number of necessary escorts in the safe section reduced, the water area in which our hunting groups based at Corfu would operate would be reduced from its present size, both ends of the barrage would rest in friendly soil eliminating the necessity for the military operations at one end, the project could be pushed through now, or as soon as mines could be provided without waiting on military events on the Western Front. The Bureau of Ordnance has studied the conditions and is of the opinion that the depth of water between the points indicated offer no bar to our form of mines. If the original plan is adhered to it will still require the further closing of the Dardanelles by separate barrage. Especially does this latter operation seem necessary in view of the present Russian situation.
Finally the Department will agree to furnish the mines necessary for any barrage* in the Mediterranean Sea (*project ) or Adriatic Sea, and it is willing to furnish whatever fast mine laying ships it can find, if fast ships are required but in this matter it expects Italy or France to contribute any ships that are idle and may be so used, the entire mine laying project to be handled by our personnel. The Department is also willing to discuss this or any other similar plan further but is inclined from an estimate of the general military situation to the opinion that the Cape Bon to Sicily project if practicable should come first, in which case it would attempt to handle the mine portions of the operation and that this operation should be undertaken as early as practicable.
Second. that the Adriatic Sea project can only be put into effect later, must wait on Military events on Western Front, and is to some extent a dissipation of military effort. <T>hird, that the Adriatic Sea project alone, without blocking the Dardanelles is not a complete project. Fourth, that the value of both Adriatic Sea and Dardanelles projects are largely dependent upon the military situation on Macedonian Front. 16026. 6489.