Second Lieutenant Raymond L. Jack, United States Coast Guard Cutter Seneca, to Rear Admiral Albert P. Niblack, Commander, Patrol Forces Based on Gibraltar
3 July, 1918.
From: Second Lieutenant R. L. Jack, U.S. Coast Guard.
To : Commander, Patrol Squadrons Based on Gibraltar.
Via : Commanding Officer.
Subject: Study of Submarine Tactics.
Reference: (a) Letter from Second Lieut. R.L.Jack, U.S.C.G. to Commander, Patrol Squadrons Based on Gibraltar, dated May 25, 1918;
(b) No. N 60, H.M.Dockyard, 4 June, 1918 (Memorandum).
Inclosures: Copy of letter from Second Lieut. R.L.Jack, U.S.C.G., to Commanding Officer, Seneca, dated June 20, 1918.
1. In connection with references (a) and (b), it is suggested that a class for officers engaged in submarine strafing be held at H.M.Dockyard at frequent intervals and plotting board exercises worked out.
2. Let Royal Navy submarine commanders take the place of “enemy vessels” and our own commanding officers take the place of “attacking vessels”, and work out some such plan as the following:
3. Let three officers work together – one as an Umpire, the second as commanding officer of an attacking vessel, and the third as commanding officer of the submarine. Each officer to be provided with a stop watch, and each of the “commanding officers” with plotting boards built on lines suggested in references (a) and (b).
4. The Umpire will call, in case of reference (a), “Attack”, or, in case of reference (b), “Periscope distant ----- yards, --- degrees, green (or red)”. Now the commanding officer of the submarine will attempt to escape or attack, as he desires, and the commanding officer of the surface craft will proceed to attack and place a barrage around or on the submarine. Each time he fires a depth charge he will call “Fire”. The Umpire will record the time, and the commanding officers of the submarine and surface vessel will respectively place on the plotting boards a submarine or a depth charge, representing the location of the submarine or depth charge at the instant of the command “Fire”.
5. The submarines and depth charges should be constructed to scale (in case of depth charges the destructive area should be represented by a disc prepared to scale). When the commanding officer of the surface vessel has dropped all the depth charges he desires he shall call “Attack finished”. Then the two boards will be compared, and the Umpire will decide if the attack has been successful.
6. With some such scheme as this, old plans of attack may be studied and new plans developed, and the officers of surface craft will also learn more about what a submarine can do and can not do.