NORTH CHARLESTON, S.C. — 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.
The Hunley’s eight-man crew and five Union soldiers aboard the Housatonic, which was built in Boston, died in the battle.
Scientists said Monday that the Hunley apparently was fewer 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. 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.
Conservator Paul Mardikian found evidence of a copper sleeve. ‘‘The sleeve is an indication the torpedo was attached to the end of the spar,’’ he said. It may be that the crew — found at their seats when the sub was raised with no evidence of an attempt to abandon ship — had been knocked out by the concussion of an explosion so close by.