On a dark night in February of 1864, the H.L. Hunley, the first submarine to sink an enemy ship in combat, torpedoed the Union blockade ship USS Housatonic, a feat that would not be repeated for another 50 years. But fate was not kind to the Hunley that night as it sank with all of its crew on board before it could return to shore. Considered by many to be the Civil War’s greatest mystery, the Hunley’s demise and its resting place have been a topic of discussion for...