Answer: CSS H. L. Hunley
CSS Hunley was built in Mobile, Alabama at a cost of $30,000. She was named after one of her designers, Horace Lawson Hunley. The boat was about 40 feet long and had a crew of one officer and seven men. She sank several times during testing, killing 13 men, including Hunley. On the night of February 17, 1864, Hunley, under the command of Lt. George E. Dixon, attacked the sloop USS Housatonic, one of the Union ships blockading the port of Charleston, South Carolina. Hunley planted a "spar torpedo," (a 90 pound charge of gunpowder) in Housatonic's hull, backed away, and detonated it. Housatonic sank very quickly; five of her crew were killed in the attack.
The Hunley never made it back to port, although it is known that she survived the attack, because her signals were seen by those on shore. Her wreckage was located in 1995, and was raised in 2000; it is now undergoing restoration. It is now thought that Hunley sank because her crew ran out of air while returning to port, and died of asphyxiation. The remains of the crew were recovered and identified through military records and DNA testing. They were buried with full military honors in Charleston's Magnolia Cemetary on April 17, 2004.