Those who do not learn history are doomed to repeat it—I think it was Ronald Reagan who said that. If not, the point is clear enough. For over a century, Civil War historians have wondered what exactly happened to the famed Confederate submarine the CSS H.L. Hunley. The submarine never returned from its inaugural voyage where it sunk the Union’s USS Housatonic in the Charleston Harbor.
In 1995, the submarine was located beneath sand and shells by novelist Clive Cussler’s National Underwater and Marine Agency. Five years later, the well-preserved wreck of Hunley, with its eight crew still at their stations and Dixon still with his lucky coin, was raised from its murky grave and brought to the Warren Lasch Conservation Center in North Charleston where it was placed in a 90,000-gallon freshwater conservation tank. The crew of Hunley were given a proper burial in 2004, and an international team of scientists studying the wreck believe they are close to solving the mystery of what happened to them in the final moments of their daring mission.
Arstechnica explains that since the recovery, teams of researchers have gone about trying to figure out exactly what happened to sink the great Confederate weapon.
Prior theories that the sub had been sunk by shots from the Housatonic were dispelled. Some speculated that the air supply had gone foul, and the crew had suffocated. But theories rapidly shifted when it was discovered exactly how the Hunley delivered its attack against the Housatonic. Now researchers from Duke University have provided historians with some more confidence in the probable reason the Hunley never returned from its mission: the crew was likely killed by the sub's own weapon: what amounted to a bomb on a stick.
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In a recently published paper, Naval Surface Warfare Center biomedical engineer Rachel M. Lance and her colleagues recounted how they recreated (in small-scale) the conditions as the Hunley delivered its torpedo to the Housatonic's hull. Using a scale model of the submarine, dubbed the "CSS Tiny," the researchers performed a series of tests to determine how much of a pressure wave would have been transmitted through the hull of the submarine.
Aside from its ballast tanks, the Hunley was essentially a single-walled iron tube. While she may have been relatively invulnerable to rifle fire, the Hunley would have transmitted any sound or pressure from the water around the sub to the crew within its cramped, 4-foot high interior. Lance, who conducted the research as part of her PhD thesis in biomedical engineering at Duke University, theorized that the pressure of the explosion of the Hunley's torpedo could have caused enough of a shock inside the sub to kill the crew through a combination of "air blast trauma" to their lungs and traumatic brain injuries.
According to this research, the crew would have been concussed, likely unconscious, and definitely unable to breathe. Desperation led the Confederacy to push through the development and building of the CSS H.L. Hunley, and the results were horrific for everyone on both sides. Probably nothing worth learning here.