Some called it a murdering machine. But the question was: Who faced the greatest risk from this machine—the enemy or the men operating it? Eight men were jammed side by side in this cramped Civil War submarine, with walls 3½ feet apart and the ceiling about 4 feet...

"If you want to increase your success rate, double your failure rate," businessman Thomas J.Watson once said. James R. McClintock, Baxter Watson, and Horace Hunley certainly had their share of failures as they pioneered the creation of submarines during the Civil War....