The Ko-Hyoteki Ko-Gata (Target A Type A) midget submarine Ha-19/I-24tou stranded on an O’ahu beach, December 1941. Of the two-man crew, one was captured, and the other killed, presumably by drowning. The submarine is currently on display at the National Museum of the Pacific War in America.
I’ve seen two of these that attacked Sydney harbour, posed as a composite boat. I’m surprised they could fit
one person in there, after all the batteries and torpedoes.