Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Admiral William S. Benson, Chief of Naval Operations
S E C R E T 11-1-6.
20 March, 1918.
From: Force Commander.
To : Chief of Naval Operations.
Subject: Plan of Attack against Submarine suggested by Lieutenant Falge.
Reference: (a) Letter of Lieut. Falge to Chief Burdeau Ordnance; 2/14/18.
(b) Letter Bureau of Ordnance No. 32934; February 25, 1918.
(c) C.N.O. End (1st) No. 28754-3: 132/263.
The plan suggested by Lieutenant Falge in reference (a) for detecting submarines has for sometime been under consideration, and has been proposed to the Director Anti-Submarine Division of the Admiratly.
It is considered that the plan suggested has some merit and that with a suitable detection device it is possible to discern a submarine by this means.
The advisability of using a small boat in the open sea in this kind of work is however, open to question. There is no doubt that for a great deal of the time it would be impracticable to do so. Weather conditions must be very good for the successful operation of so small a boat as is described by Lieutenant Falge, especially when equipped as desired by him. Submarines would not be apt to seek a lee until long after weather conditions were too bad for such a small boat to operate.
The plan suggested of lowering such a boat from a destroyer then having the destroyer proceed to a distance of ten miles is not good policy. There is little doubt that the boat would be destroyed and crew either killed or taken prisoners, as a single offensive demonstration on its part would assuredly encompass its destruction unless immediate assistance was afforded, it is essential for the protecting destroyer to be stationed much nearer the listening boat and this at once traduces the matter of sound interference. The proper solution of the problem is an efficient sound detection device on the Destroyer and this seems nearer and nearer of accomplishment every day.
The suggestion that 500 lbs depth charges should be used is a good one and the matter of increasing the weight of depth charges is not under consideration. The depth charge settings, namely 8 0 ft for off-shore and 40 ft. for in-shore work, suggested is not considered advisable. Recent secret instructions of the German Naval Staff to German submarine Captains state that, when it is believed an attack is going to be made by Destroyers of other vessels carrying depth charges, the submarine should immediately submerge to a depth of 150 feet.
Source Note: Cy, DNA, RG 45, Entry 517B. There is a note below close: “Copy to:/Bureau of Ordnance./Lieut. Falge./Board Anti-Submarine Devices.” There is an identifier in the top right-hand corner: 1/3/J.