Ever since the Confederate submarine Hunley was discovered off the South Carolina coast, theorists have wondered what caused it to sink in 1864.
Now Clemson University researchers might have found an explanation to what caused the world’s first successful combat submarine to vanish.
Researchers discovered the Hunley’s air circulation system was not in use when the sub and her eight-man crew disappeared in 1864, the Friends of the Hunley said Wednesday in a news release.
The Hunley held enough oxygen for the crew to survive for roughly two hours, and there were only two ways to replenish the air supply, according to the release.
“One was to use the air circulation system, which was designed to be stealth and allow them to discreetly get fresh air,” it said in the release. “The only other alternative was to come to the surface and open the hatches, a potentially dangerous move if enemy ships were nearby.”
The presence of Union ships seems likely after the Hunley sank the USS Housatonic in a surprise attack on the blockade of Charleston Harbor.
In an effort to remain hidden from other members of the union fleet, the Hunley’s crew might have tried to outlast their foes and attempted to stay beneath the water’s surface, researchers said. But if the crew miscalculated the timing or thought it was too dangerous to resurface, they might have run out of oxygen, according to the release.
“The air circulation system is certainly one of many important clues to consider when trying to piece together the events of that night,” Clemson archaeologist Michael Scafuri said in the release. “Still, this finding alone does not mean the Hunley crew perished from lack of oxygen.”
Researchers are trying to determine if there was a flaw in the air system, or if the crew stopped using it to make more room in the cramped compartment.
While they try to explain why the system was disabled, researchers found the system was “intentionally disconnected and tucked underneath the crew bench,” according to the release.
The system consisted of a rubber hose that connecting snorkel tubes to hand-pumped bellows that pushed out carbon dioxide and refreshed the compartment with oxygen, Friends of the Hunley said.
The snorkel tubes were also in the lowered position when the submarine disappeared, indicating the Hunley had not surfaced, according to the release.
Studying the air system is a delicate and timely process because it was highly corroded after years in saltwater, and requires specialized conservation treatment, Friends of the Hunley said.
It is just the latest chapter in the mystery surrounding the submarine.
After signaling to shore that it had sunk the Housatonic on February 17, 1864, the Hunley vanished. After more than a century of searching for the sub, Clive Cussler’s National Underwater and Marine Agency located the vessel in 1995, Friends of the Hunley said.
Archeologists raised the ship in 2000 and have been working to solve the mystery of why the sub sank ever since, according to the release.
Now Friends of the Hunley said a team of scientists is trying to “conserve the submarine for future generations and piece together clues to solve the mystery of her disappearance.”