H. L. Hunley was a Confederate Civil War submarine developed from earlier failed submersible projects by Horace Lawson Hunley, James McClintock, and Baxter Watson to help break the Union blockade. Built at Mobile, Alabama, launched in July 1863, and sent to Charleston, she was a hand-powered craft operated by a crew of eight. The submarine twice sank in training accidents in 1863, killing thirteen men, including Hunley himself. On February 17, 1864, under Lieutenant George E. Dixon, she sank USS Housatonic outside Charleston harbor, becoming the first combat submarine to destroy an enemy warship, but was lost with her entire crew. Recovered in 2000, she marked both the promise and deadly peril of early submarine warfare.