Heat advisory in effect Sunday until 8 p.m.

Civil War submarine reveals more clues, human remains

More clues of the H.L. Hunley mystery are being revealed during conservation of the American Civil War submarine.

Researchers in a North Charleston, South Carolina, laboratory on Wednesday unveiled the crew compartment — which had been sealed by more than 130 years of ocean exposure and encrusted sediment.

“It’s that wow moment when you step back and realize what you’re doing,” Johanna Rivera, one of the submarine’s conservators told CNN affiliate WCIV.

The Confederate Navy’s Hunley was the first submarine to sink a ship in battle, sending the Housatonic to the ocean floor in February 1864. Five members of the Union vessel died; 150 others were rescued. All eight crew members of the Hunley perished.

The conservation work, which started after the Hunley was discovered in 1995, has finally exposed the sub’s entire crank shaft — used to propel the vessel by its crew.

A tooth was found embedded in sediment on one of the crank handles. Officials say it wound up there “post mortem,” after decomposition of a body.

Inside they also found remnants of textiles and a thin metal wrap around the hand crank — showing how the crew operated the sub.

“When you’re turning an iron bar in front of you or below you, you’re going to need something to keep your hands from chaffing or rubbing them raw,” archaeologist Michael Scafuri told WCIV.

The new findings give insight into how the submarine was operated, but the biggest mystery is still unsolved — why did it sink after its successful attack?

One scenario holds that the Hunley was swamped by or struck by a Union vessel. Or that it plunged to the sea floor to avoid detection, and never made it back up.

Restoration work on the Hunley will continue for at least another five to seven years. After the process is finished it will be moved to a museum for display.