The Record
Confederate submarine, hand-cranked by a crew of eight, armed with a spar torpedo on a ten-metre pole. On the night of 17 February 1864 off Charleston, she became the first submarine in history to sink an enemy warship, putting her torpedo into the Union sloop USS Housatonic. She never returned. Recovered in 2000 and conserved for twenty years; analysis suggests the crew were stunned unconscious by the shock of their own torpedo transmitted through the water and drowned at their stations.
The Vessel
The H. L. Hunley was a Confederate States Navy submarine built in Mobile, Alabama, in 1863 under the private direction of the engineer Horace Lawson Hunley, from whom she took her name. She was 12 metres long, roughly 1.2 metres in diameter, constructed from a cut-down cylindrical boiler with pointed ends riveted on, and was propelled by eight men turning a hand crank that drove a single three-bladed propeller. She displaced approximately 7.5 tonnes submerged and carried a crew of eight: seven crankmen and a commander who steered and managed the dive planes.
She was the third submersible Horace Hunley had built. The first, the Pioneer, had been tested at New Orleans in 1862 and scuttled when the city fell to Union forces. The second, the American Diver, had been lost in Mobile Bay in early 1863 during a test that confirmed she was underpowered. The Hunley was the improved version, with the eight-man hand crank replacing the earlier four-man design, built to attack the Union blockade of Charleston, South Carolina.
Her weapon was a "spar torpedo": a 4.5-metre wooden pole extending from her bow, tipped with a 41-kilogram copper canister containing black powder. The attack method required the submarine to approach its target below the surface, ram the spar into the target's hull below the waterline, back off, and detonate the charge by a lanyard as the submarine withdrew. The method was crude, dangerous, and unprecedented in naval warfare.
The Voyage
The Hunley was shipped by rail to Charleston in August 1863 and assigned to the Confederate naval defences of the city, which was under a progressively tightening Union blockade. Her first months in Charleston were disastrous. On 29 August 1863 she sank at her dock in an accident that killed five of her eight crew. She was raised, cleaned, and tested again. On 15 October 1863 she sank during a test dive under the personal command of Horace Hunley himself, killing Hunley and all seven crew aboard. She was raised a second time from 20 metres.
By late 1863 the Hunley had killed 13 of her crew in training accidents without harming a single Union sailor. The Confederate naval command nevertheless persisted with the submarine programme because the alternative, the continued Union blockade, was causing the starvation of Charleston. Lieutenant George E. Dixon of the Confederate States Army was appointed her new commander in late 1863; he was a twenty-seven-year-old Kentuckian with previous experience in small-boat operations and a reputation for careful leadership. Dixon and a new crew of seven spent the winter of 1863-64 practising with the Hunley in the waters off Sullivan's Island.
On the evening of 17 February 1864 the Union sloop-of-war USS Housatonic, a 1,240-ton screw sloop mounting twelve guns, was anchored on blockade station approximately 6 kilometres off Sullivan's Island. The moon was in its second quarter; the sea was calm; the tidal stream was running with the Hunley's intended course. Dixon and seven crewmen departed Breach Inlet at approximately 18:00 for the first and only combat submarine attack of the American Civil War.
The Disaster
The Hunley approached the Housatonic from the southwest at perhaps 3 knots, awash or nearly so to present minimal silhouette. She was sighted by the Union watch officer, Acting Master John Crosby, at approximately 20:45 at a distance of 90 metres. Crosby rang the alarm bell, ordered the anchor chain slipped, and directed musketry at the approaching object. Rifles fired, revolvers fired. None of the small-arms fire penetrated the Hunley's iron hull.
At approximately 20:45:30 the spar torpedo made contact with the Housatonic's starboard quarter, just forward of her mizzen mast. The detonation of the 41-kilogram black-powder charge opened an 3-metre hole in her hull below the waterline. The explosion lifted the Housatonic bodily; she settled back into the water and began to flood rapidly. She sank in 9 metres, her masts still projecting above the surface, at approximately 20:52. Five of her 160-man crew died.
The Hunley never returned to Breach Inlet. Dixon and his crew were sighted signalling toward Sullivan's Island from a short distance southeast of the Housatonic sinking at approximately 21:00 on 17 February; they were never seen again. The Hunley was officially lost. The Confederate naval command classified her missing and investigated for decades without locating the wreck. She was the first submarine in human history to sink an enemy warship in combat, and she had not come home from the attack.
The Legacy
The search for the Hunley continued, in one form or another, from 1864 until 1995. In May 1995 a salvage team working for the popular novelist Clive Cussler's National Underwater and Marine Agency located her in 8 metres of water, 300 metres from the final position of the Housatonic, buried in approximately 1 metre of sediment. The discovery was announced on 3 May 1995 and confirmed by the South Carolina Hunley Commission.
The submarine was raised from the Charleston Harbor seabed on 8 August 2000 in one of the most careful and widely-publicised maritime archaeological operations ever conducted. She was lifted by a specially-designed 27-metre truss frame that cradled her intact, avoiding any structural stress on the 136-year-old iron hull. She was transferred to the Warren Lasch Conservation Center in North Charleston, South Carolina, where she has remained under ongoing electrolytic conservation since 2000.
The conservation and forensic investigation produced the modern understanding of what killed Dixon and his crew. Skeletal analysis of the recovered remains of all eight crew members, conducted by the Smithsonian Institution's forensic anthropology department under Doug Owsley, showed that they had died at their stations, each man at his own crank handle, in a posture consistent with instantaneous death or incapacitation rather than with the drowning characteristic of a flooded submarine. The cause, according to the 2017 forensic engineering reconstruction published by Rachel Lance of Duke University, was the blast wave from the Hunley's own torpedo transmitted through the water and through the Hunley's iron hull to the lungs of the crew, producing instant pulmonary barotrauma. The Hunley killed herself with her own weapon.
The recovered remains of the eight Confederate submariners were buried with full military honours at Magnolia Cemetery in Charleston on 17 April 2004, exactly 140 years and two months after the Housatonic attack. The ceremony was attended by an estimated 50,000 people, the largest Civil War memorial service of the twenty-first century. The Hunley is on display at the Warren Lasch Conservation Center, where her ongoing conservation continues. She is the oldest surviving combat submarine, the only submarine in history whose killing of an enemy warship was confirmed by the corresponding loss of her own crew, and the first submarine to kill anyone in war.