What Confederate submarine became the first combat submarine to sink an enemy warship? H. L. Hunley. The hand-powered Confederate submarine achieved this milestone on February 17, 1864, when it attacked the Union sloop-of-war USS Housatonic outside Charleston Harbor.
Hunley approached under the surface and drove a spar torpedo into Housatonic's hull. The explosive sank the 1,240-ton warship within minutes, killing five Union sailors. The attack was a major technological first, but it was also a devastatingly short-lived victory: Hunley and all eight members of her crew disappeared after the explosion.
The submarine was named for Horace Lawson Hunley, one of its financial backers and designers. It had already suffered fatal accidents during testing, including one that killed Hunley himself. The wreck was located in 1995 and raised in 2000. Although often called CSS Hunley, it was operated under Confederate Army control and was not officially commissioned as a Confederate Navy ship.