FILE - The Confederate submarine H.L. Hunley sits in a conservation tank after a steel truss that had surrounded it was removed in this Jan. 12, 2012 file photo taken at a conservation lab in North Charleston, S.C. Scientists say a pole on the front of the Confederate submarine H.L. Hunley designed to plant explosives on enemy ships may hold a key clue to its sinking during the Civil War. The experts are to release their findings Monday Jan. 28, 2013 at the North Charleston lab where the hand-cranked sub is being preserved and studied. (AP Photo/Bruce Smith, File)FILE - The Confederate submarine H.L. Hunley sits in a conservation tank after a steel truss that had surrounded it was removed in this Jan. 12, 2012 file photo taken at a conservation lab in North Charleston, S.C. Scientists say a pole on the front of the Confederate submarine H.L. Hunley designed to plant explosives on enemy ships may hold a key clue to its sinking during the Civil War. The experts are to release their findings Monday Jan. 28, 2013 at the North Charleston lab where the hand-cranked sub is being preserved and studied. (AP Photo/Bruce Smith, File)
NORTH CHARLESTON, S.C. (AP) — Researchers say they may have the final clues needed to solve the mystery of the Confederate submarine H.L. Hunley, which never resurfaced after it became the first sub in history to sink an enemy warship, taking its eight-man crew to a watery grave.
Scientists said Monday that the Hunley apparently was less than 20 feet away from the Housatonic when the crew ignited a torpedo that sank the Union blockade ship off South Carolina in 1864. That means it may have been close enough for the crew to be knocked unconscious by the explosion, long enough that they may have died before awakening.
For years, historians thought the Hunley was much farther away and had speculated the crew ran out of air before they were able to return to shore.
The discovery was based on a recent examination of the spar — the iron pole in front of the hand-cranked sub that held the torpedo.
The Hunley, built in Mobile, Ala., and deployed off Charleston in an attempt to break the Union blockade during the Civil War, was finally found in 1995. It was raised five years later and brought to a lab in North Charleston, where it is being conserved.
Conservator Paul Mardikian had to remove material crusted onto one end of the spar after 150 years at the bottom of the ocean. Beneath the muck he found evidence of a cooper sleeve. The sleeve is in keeping with a diagram of the purported design of a Hunley torpedo that a Union general acquired after the war and is in the National Archives in Washington.
"The sleeve is an indication the torpedo was attached to the end of the spar," Mardikian said. He said the rest of the 16-foot spar shows deformities in keeping with it being bent during an explosion.
Now it may be that the crew, found at their seats when the sub was raised with no evidence of an attempt to abandon ship, may have been knocked out by the concussion of an explosion so close by, said Lt. Gov. Glenn McConnell, a member of the South Carolina Hunley Commission.
"I think the focus now goes down to the seconds and minutes around the attack on the Housatonic," he said. "Did the crew get knocked out? Did some of them get knocked out? Did it cause rivets to come loose and the water rush into the hull?"
The final answers will come when scientists begin to remove encrustations from the outer hull, a process that will begin later this year. McConnell said scientists will also arrange to have a computer simulation of the attack created based on the new information. The simulation might be able to tell what effect the explosion would have on the nearby sub.
Maria Jacobsen, the senior archaeologist on the project, said small models might also be used to recreate the attack.
Ironically, the crucial information was literally at the feet of scientists for years.
The spar has long been on display to the public in a case at Clemson University's Warren Lasch Conservation Lab where the Hunley is being conserved. With other priorities on the sub itself, it wasn't until last fall that Mardikian began the slow work of removing encrustations from the spar.
Scientists X-rayed the spar early on and found the denser material that proved to be the cooper sleeve. But Jacobsen said it had long been thought it was some sort of device to release the torpedo itself.
Finding evidence of the attached torpedo is "not only extremely unexpected, it's extremely critical," she said. "What we know now is the weapons system exploded at the end of the spar. That is very, very significant."