H.L. Hunley, a small, hand-powered submarine, was privately built at Mobile, Alabama, in 1863, based on plans furnished by Horace Lawson Hunley, James R. McClintock and Baxter Watson. Her construction was sponsored by Mr. Hunley and superintended by Confederate officers W.A. Alexander and G.E. Dixon. Following trials in Mobile Bay, she was transported to Charleston, South Carolina, in August 1863 to serve in the defense of that port. On 29 August, while moored to a steamer, the submarine was accidently pulled over on its side and sank, drowning five members of her crew. After salvage, she was given a new crew and began a series of tests. However, during diving trials on 15 October 1863, she failed to surface. Horace Lawson Hunley, who was directing her operation, and the rest of her men were drowned.

H.L. Hunley was again raised and repaired. With a third crew, and under orders to only operate on the surface, she began a series of attempts to attack United States Navy ships on blockade duty off Charleston. On 17 February 1864, these efforts were successful. H.L. Hunley approached the steam sloop of war USS Housatonic and detonated a spar torpedo against her side. The Federal ship sank rapidly, becoming the first warship to be lost to a submarine's attack.

However, H.L. Hunley did not return from this mission, and was presumed lost with all hands. Her fate remained a mystery for over 131 years, until May 1995, when a search led by author Clive Cussler located her wreck. On 8 August 2000, following extensive preliminary work, the H.L. Hunley was raised and taken to a conservation facility at the former Charleston Naval Base. At present, she is the subject of a careful preservation effort that ultimately should place her in suitable condition for general public exhibition.