I saw a segment about this early submarine last night on TV. The Confederates were trying to break a blockade of supplies overseas. The submarine wasn't the first designed, but it was still early in development. It was tested and improved upon for seven months. Thirteen people had died during this time. Regardless, eight men volunteered. They were cramped in a very tiny shell, and the power was all human, driven by rapidly cranking. They managed to accomplish their goal of torpedoing and sinking a ship, but they never made it home. When the sub was finally discovered over 130 years later, the men appeared to be slumped over, and had not taken damage from their own torpedo, as previously postulated. It appeared they simply ran out of air. What do you think of their sacrifice? They knew the odds of coming back alive were low, but went anyway.
