Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Destroyer Flotillas
U.S. NAVAL FORCES OPERATING IN EUROPEAN WATERS.
U.S. MELVILLE, FLAGSHIP.
File 5321-1. BASE SIX,
31 October, 1918.
From: Force Commander.
To: Destroyer Flotillas, Queenstown.
Subject: Anti-Submarine Equipment and Tactics.
Reference: (a) Blue Print of Loading Device for Y-gun.
and Thornycroft Thrower.
(b) Force Comdr’s Let. M-4 No. 19495 of 28 May, 1918.
(c) Force Comdr’s Let. M-4- No. 31433 of 26 August 1918.
(d) Force Comdr’s Let. No. 1593-3- of 19 June 1918.
(e) Force Comdr’s Let. No. 1359-3 of 3 August 1918.
(f) Force Comdr’s Let. No. 5321-1 of 3 August 1918.
(g) Report of Conference at British Admiralty.
Enclosure: Copy of Reference (a).
1. The Force Commander urges the development and improvement of anti-submarine methods by the sea-going element of the Destroyer Forces.
2. The successful attack recently made upon one of the convoys under American escort by an enemy submarine indicates the necessity for a well defined Flotillas doctrine outlining means of executing a combined counter-attack by a group of destroyers in such cases, and make it imperative that this Forceprepare, and put into execution at the earliest date, plans which will present the best chances of successfully destroying, or seriously injuring an enemy attempting such an attack.
3. In considering the question, there are two separate and distinct requirements which demand attention.
First, the development and use of our anti-submarine armament to the limit of its capabilities.
Second, the preparation and issue of practical plans of combined attack and the indoctrination of the Force in their use.
4. As to the first step, the following progress has been made:
(a) Reference (b) directs the installation of one Y-gun and two Thornycroft Throwers (or two Y-guns) and the carrying of 50 depth charges by each destroyer.
(b) Reference (c) directs that the 750 tons destroyers remove their quarter-deck torpedo tube and improve their Y-gun and Thornycroft leading facilities to the maximum.
(c) Reference (d) directs the inauguration of complete and carefully prepared depth charge policies or doctrines on ships of the Force.
(d) Various correspondence has shown that it is possible to project depth charges 40 yards with the Thornycroft Thrower and 98 yards with the Y-gun (using two pound impulse).
(e) Reference (e) indicates that these projectors may be reloaded and dired [i.e., fired] rapidly and steadily for a number of salvos.
(f) One destroyer has an equipment which permits her to lay an absolute effective barrage 233 yards wide and 1,110 yards long. She carries one Y-gun, two Thornycroft Throwers, loading apparatus, and 50 depth charges. She fired 10 salvos 10 seconds apart, each salvo consisting of five charges as follows: One from stern; one from each Thornycroft (40 yards); two from the Y-gun (98) yards.
(g) Reference (a), enclosure (1) shows a simple light and effective loading tray which can be used wither with the Y-gun or Thornycroft Thrower. This is easily installed by the ship’s force. It has beenused on a sub-chaser loading with an untrained crew,qevery twelve seconds.
5. The above references show that a wide and effective sustained barrage is feasible, and each Commanding Officer is enjoined to at once carefully investigate the possibilities in his ship, making every attempt to approach the standard indicated in sub-paragraph (f). It is fully realized that the rolling and pitching of a ship in rough weather will have a direct influence on the speed of reloading the depth charge throwers. Addition of unnecessary weight should be avoided as much as possible, also apparatus that has notbeen tried and found efficient. In this connection attention is directed to the urgent necessity of carefully observing all safety precautions. Speed in reloading and handling the depth charges should not be obtained at a sacrifice of any degree of safety assistance possible in helping Commanding Officers to develop their apparatus.
6. In taking up the “Second” requirement, the preparation of plans of combined attack, reference (f) is the only plan for combined attack now in use in the Flotillas as far as is known. This plan, however, does not meet all the requirements of the situation. Reference(g), the Devenport Flotilla’s Plan of Attack, gives additional information along these lines, but is still incomplete.
7. The members of the Staff on board the MELVILLE have the necessary equipment to make studies of the possibilities of the situation and to examine thoroughly the requirements, and are prepared to investigate, develop, and draw up in concrete form such suggestions as may be presented by the officers of the American and British Forces operating from this Base. They have provided themselves with the necessary draughtmen, plotting boards and material and hope to handle the problems presented to them.
8. The ideas and criticism must, however, come from the Forces and sea and the verdict as to the practicability of the final plans rests solely with the personnel of such Forces.
9. It is the intention to take up at once preparation of the following:
(a) A system of signals which will permit a vessel of the convoy or escort to quickly notify other ships present of the presence of a submarine, indicating the submarine’s approximate location, if possible. The system to include all cases, i.e., (1) When ship is torpedoed; (2) Sights a torpedo; (3) Sees a periscope, etc.
(b) Careful determination of the areas around a convoy from which attacks may be expected.
(c) Careful determination of the position areas around a convoy in which the submarine is most likely to be for a certain period after she has delivered an attack.
(d) The most practicable and feasible methods of leaving barrages or carrying out counter-attacks in order to effectually cover such position areas.
(e) Putting in concrete form the result of these investigations.
10. Officers are requested to submit their suggestions to the MELVILLE in verbal or written form and to look over what has been accomplished on board that vessel.