New evidence from the Hunley, the world's first successful combat submarine, suggests that her eight-man crew may have died from asphyxiation rather than drowning, as was previously thought. A preliminary study of the submarine's pump system conducted by researchers at Clemson University's Warren Lasch Conservation Center shows that it was not set to bilge water out of the crew compartment that night, which could indicate that the chamber did not flood.

On the evening of February 17th, 1864, the H. L. Hunley sank the USS Housatonic. Then, after signaling to shore that the mission had been accomplished, the Hunley and her crew mysteriously vanished. Many have speculated that the submarine was damaged by the explosion, causing the vessel to take on water. When the Hunley was lifted from the ocean floor off the South Carolina coast in 2000, the pump system was in place holding the same settings it had the night she was lost. Earlier this year, the pumps were carefully removed, giving scientists the first opportunity to learn what steps, if any, the crew may have taken to save their lives.

Archaeologist Maria Jacobsen, who directs the excavation of the Hunley, called the new discovery "intriguing," but cautioned that they are only beginning to understand how the complex nine-valve pump system worked and what it can reveal about what happened that night. Discovering the purpose and position of each valve will provide critical information. "If water was rushing into the submarine at dangerous levels the night it disappeared, it is very possible the crew would have used both pumps (forward and aft) rather than rely on the bilge system alone," Jacobsen said.

Previously uncovered forensic evidence provides other clues that the crew may not have drowned. There was very little intermingling of the crew's bones, suggesting a general calmness at the time of death or a sudden event. Each man apparently died at his assigned station, and one of the two hatches was found tightly locked. If water had rushed in, it's likely that there would have been evidence of panic and the men would have rushed to the hatches, which offered the only means of escape.