They were then pounded down and sanded over flat, to reduce excess drag. And instead of being built by overlapping its iron plates like fish scales, the hull plates have been riveted to backing plates that were in turn riveted together. Other discoveries are that the steering cables and propeller shaft run inside hollow tubes that gave them protection, and two rectangular iron ballast blocks in the rear. The excavation timetable is ahead of schedule although archaeologists are still continuing to X-ray the sub to expose more of its design features. But how the rear gash got there is also a mystery, although one theory points to an anchor getting caught on the sub.
Work continues next week.
The Hunley was recovered 4 miles off Charleston Harbor in August after being lost for more than 130 years. It was discovered in May 1995 by a dive team funded by adventure novelist Clive Cussler. It became the world's first successful attack submarine in February 1864 when it sank the blockade ship USS Housatonic by ramming an explosive charge into its side. The sub is being housed in a cold-water tank at the Warren Lasch Conservation Lab in North Charleston. All rights reserved.