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Captain Samuel S. Robison, Commander, Submarine Force, to Admiral William S. Benson, Chief of Naval Operations

1st Endorsement.

15 January 1918.

From:     Commander Submarine Force.

To:       Chief of Naval Operations.

Subject:  Use of Submarines to destroy German Submarines.

     1.   Up-to-date, submarines have been the most effective weapon against enemy submarines for the simple reason that their invisibility permits them to see the enemy more frequently. Unfortunately, the percentage of hits has been very low and what has been accomplished to-date has been at considerable expenditure of torpedoes.1

     2.   As a result of this condition, the British Admiralty, at the suggestion of various submarine officers, has apparently undertaken the design and construction of a special submarine which will more nearly fulfill the special mission of submarine destruction. The service requirements of this vessel are

(a) Boat should be very fast under water.

(b) It should have as many tubes in the bow as could be fired simultaneously.

(c) The gun should be so arranged that it could be fired immediately it (the gun) submerges.2

     3.   The Force Commander believes that a submarines having the required characteristics can be more effectively used against submarines than some of the older type of submarine in use, but he does not believe that the special type, with a single screw, large storage battery capacity, and low engine power, will fill the requirements as completely as the 850 ton Government “S” class now building. The characteristics of the Government “S” submarine as regards underwater speed, is as follows:




















       " (about).





     4.   As regards engine power and storage battery power and habitability, the “S” class submarine is decidedly superior to the special type designed by the British Admiralty.

     5.   As regards torpedo armament the special type designed by the British Admiralty is undoubtedly superior for purposes of submarine destruction, and the Force Commander can see no objection to such an installation on our standard 850 ton boats of the “S” type, in place of the 4-tube arrangement in the bow; provided

1st – that the Bureau of Ordnance can supply an ample number of the special torpedoes;

2nd – that this installation can be replaced in the future with the standard 4-tube arrangement, and

3rd – that this alteration will not cause undue delay in submarine building programs.

     6.   As regards the proposed gun armament, the Force Commander has not sufficient data upon which to base an opinion. He recommends, however, a thorough investigation by the Bureau of Ordnance of the problem before attempting such an installation on our submarines.

     7.   The Force Commander’s recommendations are summarized as follows:

(a)  Ascertain the possibility of procuring the special torpedoes of the special type required, in order to utilize the shot gun principle.

(b)  Use a standard “S” class submarine and only alter the torpedo tubes, in case the design is attempted at all.

(c)  Make a thorough investigation of the proposed gun installation prior to attempting its design.

(d)  Do not attempt design at all, if it will materially delay the delivery of submarines now under construction.


Source Note: Cy, DNA, RG 45, Entry 517B. Document reference: “6674-E.”

Footnote 1: While submarines were indeed the most effective submarine hunter, British submarines had a contact to sinking ratio of thirty to one, which meant for every thirty sightings one successful attack was executed. Dwight R. Messimer, Find and Destroy: Antisubmarine Warfare in World War I (Annapolis, MD: Naval Institute Press, 2001), 141.

Footnote 2: This was the “R-class” submarines, the first true hunter-killer submarine class. It was a small boat (160 feet long and 500 tons), boasted a top underwater speed of fifteen knots that it could be sustain for thirty minutes, and six 18-inch forward torpedo tubes. They were, however, terrible sea boats when on the surface. Five of these submarines were delivered by war’s end and there is no evidence that U.S. submarines were fitted out with any of this technology. Ibid., 145-46.