WEST BETHESDA, Md. –
Students of engineering from around the world participating in the 14th biennial International Human-Powered Submarine Races (ISR) June 25-30 were enlightened on the historical significance of the human-powered submarine.
Personnel from the Naval History and Heritage Command (NHHC) were at the Naval Surface Warfare Center, Carderock Division in West Bethesda, Maryland, talking to participants, race guests and Carderock staff about the mystery that surrounds one of the Navy's first human-powered submarines: H.L. Hunley.
According to Heather Brown, NHHC historian and co-author of the book H.L. Hunley: Recovery Operations, Hunley - officially part of the Confederate Navy built in 1863 by Parks and Lyons of Mobile, Alabama - was the first sub in U.S. history to sink an enemy warship in combat.
"There was a cordon of Union vessels blocking access to Charleston, South Carolina, in an effort to try to strangle off merchant shipping, so Hunley targeted one of those ships that was easier to get to, USS Housatonic," Brown said.
Like the submarines built and raced during ISR, Hunley was human-powered. A product of its time, Brown noted that this was the only efficient way to power a submarine because at the time the primary artificial mode of propulsion was steam power, which would not work in an underwater environment. Hunley was operated by a seven-man team on a central crank shaft with an eighth man to pilot.
"On Feb. 17, 1864, they cranked out to sea four miles and they had a spar-mounted torpedo - today's equivalent of a mine - fixed on a spar that was 16 feet long that came out from the bottom of the bow. With this they rammed into the side of Housatonic and the explosive detonated and sank the ship in about five minutes. The water was very shallow so the rigging was still sticking up out of the water of Housatonic, so most of the men were able to climb up and get above the water."
Five men aboard Housatonic died from the explosion, but it would be the fate of the men in Hunley that would remain a mystery until recent decades. According to Brown, after the attack, Hunley just disappeared.
"There was over 100 years of speculation about what happened to it and a lot of people had been looking for it since then, and they did find it using a magnetometer survey. It was buried 3 feet under the seabed at that point in 1995 when they found it off the coast of South Carolina, only about 800 feet away from wreckage of Housatonic - so it didn't get very far."
Brown said some speculated the crew of Hunley might have been trying to get out of the way of an incoming ship so they were not hit or spotted; others have speculated that it wasn't ebb tide at the time and the sub was lost out to sea while waiting for the flood tide to start coming in so they could get to shore.
To help understand the mystery of what caused Hunley to sink immediately after it carried out the attack on Housatonic, engineers from several Warfare Centers, including Carderock, used advanced digital modeling and simulation techniques to study the effects of the explosion on Hunley and its crew, and the hull's seagoing characteristics. The exact cause of Hunley's sinking is still a mystery.
According to literature provided by NHHC, Hunley was hoisted from the depths of the sea in the summer of 2000, finally completing its voyage back to Charleston for preservation and examination. Brown and Mass Communications Specialist 1st Class Cliff Davis shared with visitors an artifact from Housatonic that was pulled from the remains of the ship after some minor excavation of what remains of the vessel.
The human-powered submarine in one and two-person designs has remained a staple of ISR. NHHC staff explained a brief history of the evolution of the Navy's submarines. Davis pointed out that Hunley had an average speed of 4 knots, while many of the submarines designed by the students operate within the 5- to 6-knot range, a true testament to the advancements in engineering and the capabilities of the students involved with the races.
The ISR has been a premier science, technology, engineering and math (STEM) event for 28 years; it is sponsored by the Foundation for Underwater Research and Education (FURE) and hosted by Carderock, the Office of Naval Research and Program Executive Office Submarines. ISR challenges students to design, build and race a one- or two-person human-powered submarine on an underwater course.