What sunk a sub powered by cranking by hand?
Scientists near the city where the Civil War began will soak a Confederate submarine in a chemical bath to reveal its hull for the first time in 150 years. They want to solve the mystery of the demise of the first sub to sink an enemy warship
The hand-cranked H.L. Hunley rests in a 76,000-gallon conservation tank. It will be treated with a solution of sodium hydroxide for about three months to loosen the encrustation on the hull and interior. Then the sub will soak in the chemical bath for at least four more years to prevent further corrosion.
Eventually the Hunley will be put on display in a new museum in North Charleston.
Conservationists will drain the tank each day. Wearing protective gear, they will use hand tools to remove the hard sand, sediment and rust coating. Then they will refill the tank each evening.
"This is the end of the beginning" of the preservation work, said Nestor Gonzalez-Pereyra, the associate director of the Lasch Conservation Center at Clemson University's Restoration Institute. "In a year we may be able to have the clues."
Removing the encrustation could yield clues to its sinking off Charleston, S.C., in February 1864. The war had begun with the bombardment of Fort Sumter in Charleston Harbor three years earlier.
The 40-foot sub and its crew of eight had set off a powder charge that sank the Union blockade ship USS Housatonic. The Confederacy wanted to break a Union blockade of Charleston. But the Hunley never returned and just why remains a mystery.
The wreck was discovered off the coast in 1995. The silt-filled interior was excavated and the remains of the crewmen removed.
Last year, scientists announced it appears the charge that sank the Houstonic was attached to the 16-foot spar at the front of the sub. That could mean the crew was knocked unconscious and died before awakening. A closer look at the hull may provide clues.
Critical thinking challenge: Why was the Hunley powered by people instead of an engine? Did engines that could operate underwater exist in the 1860s?