I used to be huge into the whole Ironclad history in the civil war (with the Monitor and the Merrimac duking it out as the first real armored ships) and these subs were always brought up as deathtraps, there were some on the Union side as well that did slightly better, but since they were basically just holding explosives on the end of a stick out and pedaling/pumping a propeller in an underwater bucket, it tended not to go too well for the operators.