On the clear but chilly night of February 17, 1864, John Crosby stood on the deck of USS Housatonic a little less than six miles and three years removed from the launching point of the Civil War, Fort Sumter. The moonlight shimmered on Charleston Harbor’s still surface as Housatonic patrolled the South Carolina waters as part of the Union naval blockade that was slowly strangling the Confederacy.
As Crosby gazed out at the placid harbor around 8:45 p.m., Housatonic’s officer of the deck suddenly saw something shatter the water’s glassy surface only 100 yards away on the starboard side. At first, Crosby thought it could be a surfacing porpoise or perhaps a log. But as the murky shadow rippled closer to the warship, the Navy officer sounded the alarm as he realized that the strange object closing in on Housatonic was actually a cutting-edge naval weapon—a submarine.
Based on information gleaned from Confederate deserters, Union ships had been on alert for undersea vessels lurking in Charleston Harbor. Only four months before, USS New Ironsides had been partially damaged in an attack by the semi-submersible CSS David, and this windless, moonlit winter night offered perfect conditions for operating the approaching submarine, H.L. Hunley.
As all hands raced to their stations on Housatonic, seven Confederate sailors inside the primitive submarine turned a handcrank that powered the propeller as another man steered toward the 1,240-ton sloop-of-war. Even if they hadn’t been bearing down on a mighty warship, the eight men were already undertaking a dangerous mission simply by being inside the submarine that had already claimed the lives of 13 men, including its inventor, during training exercises.
The undersea vessel had been privately constructed in Mobile, Alabama, based on the plans of marine engineer Horace Lawson Hunley. Although Crosby initially thought he spotted a porpoise, the submarine more closely resembled a whale. It was constructed out of a 40-foot-long cylindrical iron steam boiler with a tapered bow and s