The painstaking restoration of this famous Civil War submarine has been going on since 2000, when it was raised from Charleston Harbor. It's pretty hard to visualize what the H.L. Hunley looked like from this photo of the rusted hull. Two drawings below from the Naval Historical Center show how a hand cranked submarine worked and what it looked like in its heyday.

Bruce Smith / AP
The Confederate submarine H.L. Hunley rests on its side as workers adjust slings to move it upright on Wednesday, June 22 at a conservation lab in North Charleston, S.C. When the process is completed, the hand-cranked sub will be upright for the first time since it sank with its crew of eight in 1864.

U.S. Naval Historical Center Photo
Confederate submarine H.L. Hunley (1863-1864) Inboard profile and plan drawings, after sketches by W.A. Alexander, who directed her construction.

Courtesy of the Navy Art Collect
Confederate Submarine H.L. Hunley (1863-1864).Sepia wash drawing by R.G. Skerrett, 1902, after a painting then held by the Confederate Memorial Literary Society Museum, Richmond, Virginia.