Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to All Forces
U.S. NAVAL FORCES OPERATING IN EUROPEAN WATERS
U.S.S. MELVILLE, Flagship.
CONFINDENTIAL May 14, 1918.
CIRCULAR LETTER NO. 35.
From: Force Commander.
To : All Forces.
SUBJECT: U.S. Depth Charges, Mark 11, Mod. 1.
1. Information has been received from the Bureau of Ordnance concerning further experiments with Mark 11, Mod. 1, 300 lb. U.S. depth charges. The experiments indicate that these charges will countermine at distances up to 150 feet; they will not countermine at a distance of 200 feet and above.
2. The rate of sinking has been determined as 6 feet per second.
3. In successive laying of depth charges in accordance with approved tactics the time interval should be so regulated that the distance between charges will be not less than 200 feet.
Source Note: Cy, DNA, RG 45, Entry 517B. Addressed below close: “Copies to:-/Brest 75/Gibraltar 35/MELVILLE 75/Aviations (Captain [Hutchinson I.] Cone) 5/Azores 15/Commander Mine Force [Joseph Strauss] 10/Sixth Battle Squadron [Hugh Rodman] 11/C-in-C Atlantic Fleet [Henry T. Mayo] 1/Operations 2/Bureau of Ordnance 2/Bunav for New Destroyers 50/Base 25, 45/Admiralty 2/Staff Representative, Paris [Richard H. Jackson] 2./Files 10.”