Naval History and Heritage Command

Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to All United States Naval Forces Operating in European Waters

COPY.

21 February, 1918.

From:-    Force Commander

To:-      All Forces.

Subject:-           Depth Charges and depth charge equipment.

Reference:- (a)     Force Commander’s circular letter on depth

                    charge policy of 7 January.1

     1.   As explained in reference (a) it is the Force Commander’s policy that depth charges should be very liberally used in all cases where there is a reasonable possibility of their proving effective. It is also considered very important to use the 300 lb. depth charges instead of smaller ones wherever this can be done.

     2.   For destroyers, tracks on the after part of the deck to carry large numbers of depth charges were prescribed. It appears, however, from the reports of the depth charge equipment from the various bases that, particularly with the older and smaller vessels, the equivalent of the standard equipment prescribed by the Admiralty has not in all cases yet been provided.

     3.   Recent important experiments have convinced the Admiralty that 300 lb.depth charges can be used on much smaller and slower vessels than had heretofore been believed possible. Very slow drifters and trawlers would find the shallower settings unsuitable with the type D depth charges and should therefore use deeper settings. It is believed that even with this restriction such vessels will do much more with 300 lb. depth charges than with smaller ones.

     4.   Owing to the possibility of mistakes being made, the extreme tests of setting a 300 lb. depth charge for 40 ft. and dropping from both steel and wooden drifters going 5 knots were tried. Both the large and the small types of trawlers had similar tests at 6½ knots with 300 lb. depth charges using a 40 ft.setting. A paddle wheel mine-sweeper dropped a 300 lb.depth charge at 7 knots with a 40 ft.setting. Things were badly shaken about and a certain amount of damage done to the machinery,but no structural damage nor anything which prevented the boats from making port safely. Type D depth charges have also been dropped from the 80 ft.motor launches with the 40 ft.setting.