At least some of these boats were later fitted with snorkels, and I-53 was also modified to carry six Kaiten. Seventeen further Type C3 units were cancelled, as were 25 units of a subsequent Type C4.
Bagnasco credits the Type C (C1, C2, and C3) submarines with sinking 16 merchant and auxiliary vessels for a total of 80,660 tons.
I-52 was lost to aircraft from USS BOGUE 800 miles southwest of the Azores while carrying rubber, gold, quinine, and Japanese engineers to German-occupied France, on 24 June 1944. I-53 survived the war, only to be scuttled off Goto Island in 1946. I-55 had been in commission only 3 months when destroyer escorts USS GILMER and the WILLIAM C. MILLER put an end to her off Saipan on 14 July, 1944.
|Units||3 (one survived)|
|Ships||I-52, I-53, I-55|
|Displacement||2,564 tons / 3,644 tons|
|Dimensions||356.5 ft x 30.5 ft x 16.75 ft|
|Machinery||2 diesels: 4,700 hp
electric motors: 1,200 hp
|Speed||17.75 knots / 6.5 knots|
|Range||21,000 nm @ 16 knots|
|Armament||6x533mm TT fwd + 2x14cm/50 cal. (19 torpedoes).|
|Max. Depth||100 m (330 feet)|
|Crew||94 officers and men|