American design for a protected cruiser submarine Type 3 dated 23 October 1920

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The Bureau of Construction and Repair was early October 1920 ordered to make a set of designs of submarine cruisers while in the future there could be a need for large submarine scouts. Protection against torpedoes and gunfire. Considered to be superior to the other three designs despite her lesser speed. Dimensions 425 (waterline) x 60 (waterline)-71 (extreme) x 26 feet. Freeboard maximum at stem 12’-0 A.P.-8 at M.P. Displacement ready to dive 13,500 tons. Speed 11 3/4 knots/4,400 shp. Cruising radius 10 knots/18,000 nautical miles. Diesel driven generators 4 units total 4,400 shp. 2 M driving motors total 4,400hp., S.B. 240 cells. Main battery 4-8” guns, 2-4” anti aircraft gun and 8-21” torpedo tubes (6 fore,2 aft). Armour heavy part barbettes 3”, tureets port 6”, sides 2”, top 3” and rear 2”. Conning tower proper 6”, top 3”, heavy part tube 3”. Protective deck total thickness 90” and 120”.

Source

U.S. Naval History and Heritage Command 1911-1925 Spring Styles Book. S-584-165