On a winter evening in 1864, the H. L. Hunley became the first combat submarine to sink a warship. The vessel successfully sank its target but then disappeared along with its eight crew members. The Hunley was not found until 1995, when a number of hypotheses as to why it sank rose to the surface. But after hundreds of hours of calculations and experiments, a North Carolina-based naval engineer came up with a new theory: the Hunley sank itself with the blast it created by firing on the USS Housatonic. Host Frank Stasio talks with biomedical engineer Rachel Lance about her obsessive work to crack the case. An article in Hakai Magazine tells the full story.