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British Admiralty Assessment of United States Submarines

Allocation of U.S. submarine



With reference to enclosed telegram can any information be give as to the qualities of these submarines so compared with our own


Both these classes (K & L) of American submarines are comparable in size with our D Class –

They are improved H class, but it is not certain that their engines are so reliable, their underwater qualities are excellent better than anything we have except ‘L’ class

Generally, they are better than our D class and able to do any work done by our ‘E’ or ‘G’ class- Their good under water speed should render them particularly suitable for under anti submarine work as carried out from Killibegs until it is certain their Engines are reliable for longer cruises from their base in point & distance 288.17.2 S.Hall

     There is good reason to believe that no class of U.S. Submarine has been really satisfactory, and the Navy Department has had to defend itself from much criticism. However, in “Hearings” for 1916, it was publicly and officially stated;-

     Re ‘K’ Class. These are the most satisfactory of U.S. Submarines. Their 2 cycle Diesel engines have given much trouble, which has now been overcome. Radius of action stated to be 5,500 miles. Tactical Cycle to be 24 days (10 out and 14 in). Very crowded both as regards crew and working space. Displacement 400/520 Lead Acid Batteries.

     Reported by Naval Attache in 1912, re ‘K’ Class:-

     Provisions for 30days, water for 8 or 10 with an electrical distiller.

     Fuel stowage estimated at 48 tons oil.

     From “Hearings”, 1916, re ‘L’ Class:-

     Tonnage 450/600. Engines 2 Cycle Diesel, which have given lubrication trouble, now rectified in light of experience of ‘K’ submarines, and said to be satisfactory. Radius of action stated to be 5,500 miles, also by Press to be 3,150 miles at 11 knots on surface.

     As far as is known ‘L’ submarines are very similar to ‘K’ Class.

R Hall    


29th August, 1917.

These submarines appear to be suitable for relieving the “D” class submarines at Killybegs and it is proposed that they should undertake that din

     An alternative would be to work from Scapa in place of the [Tess?] submarines who could then return to their base

G. Hope DID 30/8/17

Source Note: AD, UK-KeNA, Adm. 137/1437. This document was written in response to a cable from “Chief of Naval Operations, U.S. Navy” Through the “Secret Foreign Consul/24 August 1917.” See: William S. Benson to William S. Sims, 23 August 1917.

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