Submarines of the Imperial
Japanese Navy - Page 2
I-400 Class
Ko-hyoteki class submarine Grounded after Pearl
attack
Overall, despite their technical innovation, Japanese submarines were relatively unsuccessful. Due to IJN's adherence to a flawed Mahanian doctrine, they were used in offensive roles against warships, which were fast, maneuverable and well-defended compared to merchant ships. In 1942, Japanese submarines managed to sink two fleet carriers, one cruiser, and a few destroyers and other warships, and damage several others. They were not able to sustain these results afterwards, as Allied fleets were reinforced and became better organized. By the end of the war, submarines were instead often used to transport supplies to island garrisons. During the war, Japan managed to sink about 1 million tons of merchant shipping (184 ships), compared to 1.5 million tons for Great Britain (493 ships), 5.3 million tons for the U.S. (1314 ships), and 14.3 million tons for Germany (2,840 ships).
RO-33 CLASS
84 Midget subs 4 designs 1945
I-52
I-55