Recently Duke University researchers made a big splash announcing they had figured out what happened to the crew of the Confederate submarine H.L. Hunley (http://tinyurl.com/HunleyAnswer), shown in an 1863 painting by Conrad Wise Chapman. If your Civil War history is a little rusty, the 40-foot Hunley, propelled by a hand-crank for stealth, attacked and sank the Union’s USS Housatonic near Charleston, South Carolina.

The sub’s weapon was a torpedo, filled with 135 pounds of black powder and affixed to the end of a 16-foot spar that was attached to its hull (an image of a similar sub is shown, inset). Consequently, the Hunley was able to ram the bomb directly into the 1,200-ton warship’s hull below the waterline and blow it up. But then the little sub vanished.

In 1995, the Hunley was discovered only about 1,000 feet from the Housatonic. It was raised in 2000, still containing the remains of its eight-man crew, skeletons and hatches intact. But what killed them?

Duke’s three-year study involved setting off blasts near a scale model of the Hunley, and concluded that the shock wave from the explosion killed Hunley’s crew, most likely by means of “immediately fatal lung trauma.”

Not so fast, the Hunley Project says, the Duke study didn’t have all the facts, and more research is necessary to state definitively what occurred on the sub (http://tinyurl.com/DukeNo). “Though a shock wave can cause life-threatening injuries, this is something we discounted quite a while back based on the evidence,” Jamie Downs, former Alabama chief medical examiner, explained.

And the mystery continues.