Rear Admiral William S. Sims, Commander, United States Destroyers Operating from British Bases, to Secretary of the Navy Josephus Daniels
SENT: 14th May, 1917. TO: Secretary of the Navy.
THROUGH: State Department.
Replying Department’scable of May 11th. concerning net and other barrages for preventing the egress of enemy submarines (stop) The general situation is as follows based upon full conference with British Admiralty (stop) according to their experience all barrages whether of mines or nets or both are not an absolute solution for the following fundamental reason (stop) Nets do not stop submarines (stop) Mine barriers cannot be wholly effective unless they could be maintained by patrol at all points (stop) Few of the thirty thousand laid in Heligoland Bight can be watched but even if all could be patrolled it would not be wholly effective because the necessarily locally weak dispersed line of patrols can be broken by enemy concentrated attacks at any point and as often as may be necessary and mines dragged out thus releasing submarines (stop) A barrage that can be thus broken at will by concentrated attack is ineffective (stop) This subject was fully explained in my letter of May eleventh now on the way (stop) For special purposes of embarrassing enemy movements unprotected barrages of mines have always been and now are extensively used in certain areas (stop) Bitter and extensive experience has forced the abandonment of any serious attempt at blockading such passages as Scotland to Norway[,] Scotland to Shetlands, Skaggerack (stop) The one place that serious attempt at mine barrage is still attempted is the Heligoland Bight (stop) Over thirty thousand mines are now planted there and mine losses there are replaced as fast as possible about three thousand a month (stop) This of course does not and probably never can be absolutely effective for reasons above given (stop) Enemy submarines can always find passages around and through principally close in shore and through island passages and gaps dragged in mine fields (stop), The larger the number of mines however the greater degree of embarrassment to enemy (stop) Hence the more mines we can send the better and there is no limit to number that would be useful (stop) Mined area much too extensive for all to be patrolled hence no definite knowledge of number of submarines destroyed or damaged by mines (stop) Speaking generally the primary necessity is numbers of patrol craft and as previously reported too much stress cannot be laid upon the urgency of reinforcing the Allied anti-submarine forces to the extreme possible limit (stop) Defensive measures on our own coast or in any other locality and in fact all defensive considerations should be subordinated to the offensive against the submarines where they are operating (stop) Even if ene[m]y submarines appear on our own coast their operations can never be of major importance owing to the manifest limitations of distance from their bases and endurance of personnel (stop) In fact if some of the submarine efforts could be diverted into other areas than the focus of all line communications the critical nature of the present situation would undoubtedly be diminished (stop) It is the firm conviction of all British officials concerned in this problem that the most effective opposition to submarine lies in numbers of anti-submarine craft strategically disposed with the mission of dispersing the enemy submarine efforts from the critical areas and thereby forcing them to operate over such widely separated areas that their successes and our losses will be reduced below the critical point (stop) Every effort is being made to increase the British patrols (stop) The measures we take must be carried out with utmost dispatch in view of the critical degree of enemy submarine success and the general Allied military and political situation (stop) The element of time is all important (stop) The need is for destroyers anti-submarine craft tugs and mine layers in the greatest possible numbers. The British Government and Admiralty deeply appreciate the evidence of America’s desire to assist in putting down submarine menace.
NO. OF COPIES. 2. REFERENCE NO.
Source Note: C, DNA, RG 45, Entry 517.