Japanese submarines RO-57, RO-58 and RO-59 built in 1922

Medium class submarines which were in fact copies of the British L-class submarines. Described as very old. Fitted out with a marker buoy shaped as a vertical cylinder.The conning towerwas a small vertical ellipse only for access to  the submarine and with eye ports. Displacement of 889 (standard) tons and as dimensions 76.2 x 7.1 x 3.96 metres. Submergence depth 60 metres. Submerge time 60 seconds. Speed 17 (surfaced)-8 (submerged) knots. Armament 4 torpedo tubes forward. Battery 240 cells-240 V. Engines 4 cycle-2,400 shp. Semi-high tensile revited semi-double hull  

Source

U.S. Naval Technical Mission to Japan. Report S-01-1 Characteristics of Japanese naval vessels article 1 submarines. Dated January 1946.