David Bushnell built the first American sub called the Turtle Submarine in 1776. It's a one-man vessel powered by a pedal-operated propeller and armed with a keg of explosives to destroy British warships anchored in New York harbor.
Good idea, but there's a slight problem, though:
The Turtle's torpedo, a keg of powder, was to be attached to an enemy ship's hull and detonated by a time fuse. On the night of September 7, 1776, the Turtle, operated by an Army volunteer, Sergeant Ezra Lee, conducted an attack on the British ship HMS Eagle. However, the boring device that was operated from inside the oak-planked Turtle failed to penetrate the target vessel's hull. It is likely that the wooden hull was too hard to penetrate, the boring device hit a bolt or iron brace, or the operator was too exhausted to screw in the weapon.
Too exhausted after pedaling his way to the enemy! Hah! Link