Aug 13, 2014 16:53 Scientists remove encrustation on Confederate sub Scientists remove encrustation on Confederate sub Conservator Liisa Nasanen uses tools to remove encrustation from the hull of the Confederate submarine H.L. Hunley at the Warren Lasch Conservation Center in North Charleston, S.C., on Tuesday, Aug. 12, 2014. After the submarine sat in a chemical bath for more than three months to help loosen the encrustation, scientists on Tuesday began the laborious job of removing the built-up sediment by hand. The work is expected to take between eight months and a year and scientists hope that when the hull is revealed, it will provide the final clues as to why the hand-cranked sub, the first in history to sink an enemy warship, sank off South Carolina in 1864. (AP Photo/Bruce Smith) BRUCE SMITH| Associated Press Aug. 13, 2014 Comments NORTH CHARLESTON, S.C. (AP) — Scientists have started the long job of removing the encrustation from the hull of Confederate submarine H.L. Hunley. When they are finished in about a year, they hope to have the clues as to why the hand-cranked Hunley sank after becoming the first sub in history to sink an enemy warship. For more than three months, the sub has been in a conservation tank in North Charleston soaking in chemicals to help loosen the hard sand, sediment and rust clinging to the sub. Conservators on Tuesday started using tools similar to those of a dentist to gently remove the encrustation. The Hunley sank off Charleston in 1864 after sinking the Union blockade ship Housatonic. The sub was raised in 2000 and brought to the lab.