Scientists say they may have found an important clue in the mystery of why the Confederate submarine Hunley sank 140 years ago after making history by sinking an enemy warship in battle.
Archaeologists and others working to restore the submarine recovered six years ago from the bottom of the Atlantic Ocean off the coast of Sullivans Island have found evidence the forward hatch may have been opened intentionally on the night the sub sank.
The forward hatch was one of two ways crew members got in and out of the sub. It is covered in a thick layer of sand and other ocean debris, but X-rays show the hatch is open about half an inch, according to a news release Friday from the Friends of the Hunley.
Earlier reports said rods that could have been part of the hatch's watertight locking mechanism were found at the feet of the sub's commander, Lt. George Dixon.
That evidence leads those working on the sub to think the hatch may have been opened intentionally.
"The position of the lock could prove to be the most important clue we have uncovered yet and offers important insight into the possibilities surrounding the final moments before the submarine vanished that night," said Hunley Commission chairman state Sen. Glenn McConnell, R-Charleston.
If the hatch was intentionally unlocked, there are several possible explanations.
Dixon could have opened it to see if the 40-foot, hand-cranked vessel was damaged when it rammed a spar with a black powder charge into the Union blockade ship Housatonic on Feb. 17, 1864, becoming the first sub in history to sink an enemy warship.
Or Dixon could have opened the hatch to refresh the air supply in the eight-man crew compartment or to signal that it had completed its mission.
An emergency also could have led the crew to open the hatch to get out. But because the second escape hatch was found in the locked position, that theory seems less likely.
"If the Hunley crew opened the hatch, it must have been for a critical reason," said archaeologist Michael Scafuri. "Even on a calm day, three-foot swells can occur out of nowhere on the waters off Charleston. Every time the hatch was opened, the crew ran the deadly risk of getting swamped."
The Hunley sank three times, killing a total of 21 crew members.
But the reason it sank on the night of its successful mission remains a mystery.
Although scientists said the new discovery could help determine the cause of the sinking, it also is possible that the lock was damaged after the sub sank and the hatch opened while it sat on the ocean floor.