The Confederate sub was intended to liberate Charlston from the Union's effective naval blockade.

On February 17, 1864, the Confederate submarine Hunley carried out the world's first submarine attack, on the Union sloop-of-war Housatonic, sinking it in three minutes. The Hunley crew signaled their success back to shore, but they never returned. In "The Uncivilized Engine of War," scientists are trying to figure out what happened.

In 1995, after a 14-year search, a team led by author and shipwreck hunter Clive Cussler found the Hunley, completely covered by silt, close to the spot where the Housatonic had gone down. After five years of planning, the Hunley and the remains of her crew were raised from the ocean floor. Today, the sub lies suspended in slings inside a huge tank on the dock at the Charleston Navy Yard.

Soldiers' personal effects such as this coin, have been found in excavations of the Hunley

Archeologists have recovered the skeletons of all eight crew members, their clothing, shoes and personal possessions - all extraordinarily well preserved by a fine silt painstakingly removed one spoonful at a time.

Why did the Hunley sink? An X-ray examination of the sub suggests the forward hatch is still open. The crew had to have opened the hatch on the surface to signal their success to shore. But then as they hurried to flee the scene, something--perhaps an approaching Union ship--must have caused them to dive. In their haste, did they fail to lock the hatch fully? Did it spring open? We may never know for sure.

For more on this topic, see the web feature:
Raising Sunken Ships