https://en.wikipedia.org/wiki/H._L._Hunley_(submarine)Wikipedia wrote:H. L. Hunley, often referred to as Hunley, was a submarine of the Confederate States of America that played a small part in the American Civil War. Hunley demonstrated the advantages and the dangers of undersea warfare. She was the first combat submarine to sink a warship, although Hunley was not completely submerged and, following her successful attack, was lost along with her crew before she could return to base.
1864 painting of H. L. Hunley by Conrad Wise Chapman
New research sheds some light on its fate:
http://www.heritagedaily.com/2017/08/confederate-submarine-crew-killed-weapon/116346Heritage Daily wrote:Confederate submarine crew killed by their own weapon
The Hunley’s first and last combat mission occurred during the Civil War on Feb. 17, 1864, when it sank a 1,200-ton Union warship, the USS Housatonic, outside Charleston Harbor, South Carolina. The Hunley delivered a blast from 135 pounds of black powder below the waterline at the stern of the Housatonic, sinking the Union ship in less than five minutes. Housatonic lost five seamen, but came to rest upright in 30 feet of water, which allowed the remaining crew to be rescued after climbing the rigging and deploying lifeboats.
The fate of the crew of the 40-foot Hunley, however, remained a mystery until 1995, when the submarine was discovered about 300 meters away from the Housatonic’s resting place. Raised in 2000, the submarine is currently undergoing study and conservation in Charleston by a team of Clemson University scientists.
Initially, the discovery of the submarine only seemed to deepen the mystery. The crewmen’s skeletons were found still at their stations along a hand-crank that drove the cigar-shaped craft. They suffered no broken bones, the bilge pumps hadn’t been used and the air hatches were closed. Except for a hole in one conning tower and a small window that may have been broken, the sub was remarkably intact.
The Hunley’s torpedo was not a self-propelled bomb, as we think of them now. Rather, it was a copper keg of gunpowder held ahead and slightly below the Hunley’s bow on a 16-foot pole called a spar. The sub rammed this spar into the enemy ship’s hull and the bomb exploded. The furthest any of the crew was from the blast was about 42 feet.
Lance says the crew died instantly from the force of the explosion travelling through the soft tissues of their bodies, especially their lungs and brains. She says the crippled sub then drifted out on a falling tide and slowly took on water before sinking.
“This is the characteristic trauma of blast victims, they call it ‘blast lung,'” said Lance, who worked as a biomechanist at the U.S. Navy’s base in Panama City, Florida for three years before entering graduate school at Duke. “You have an instant fatality that leaves no marks on the skeletal remains. Unfortunately, the soft tissues that would show us what happened have decomposed in the past hundred years.”
Blast-lung is a phenomenon of something Lance calls “the hot chocolate effect.” The shockwave of the blast would travel about 1500 meters per second in water, and 340 m/sec in air. “When you mix these speeds together in a frothy combination like the human lungs, or hot chocolate, it combines and it ends up making the energy go slower than it would in either one,” thus amplifying the tissue damage. Lance said that when it crossed the lungs of the crewmen, the shockwave was slowed to about 30 m/s.
While a normal blast shockwave travelling in air should last less than 10 milliseconds, Lance calculated that the Hunley crew’s lungs were subjected to 60 milliseconds or more of trauma.