The IJN I-400 Class submarine was the greatest submarine in WW ? as well as the largest worldwide before the development of nuclear submarines in 1960s.I-400 had enough fuel to go around the entire world one . 5 times and was able to carry 3 Aichi M 6A 1�Seiran� aircraft that would be put together for trip within seconds. Among their missions, that has been never performed, apparently would be to make use of the aircraft to drop bacteriological bombs on U.S. towns and cities. Nevertheless the bacteriological bombs couldn't be ready with time .Later, a mission was to bomb the Panama Canal to cut the supply lines of Allied forces but canceled eventually. The I-400 and I-401 were captured at ocean weekly following the Japanese surrendered in 1945.
