NORTH CHARLESTON, SC (WCSC) - The historic Civil War submarine which sank in the Charleston Harbor is looking more and more like it once did.
Archaeologists and conservationists working on the H.L. Hunley showed off their latest efforts at the Warren Lasch Conservation Center Wednesday.
Mystery is still embedded in the metal walls of the historic submarine, but archeologists and conservationists are gaining more insight.
"[Years ago] we couldn't see many of the seam lines or the structural features of the submarine that are now exposed," said archaeologist Michael Scafuri. "The hull plates and the details on some of the features like the bow, two hatches or conning towers, [can now be seen] as they were when the submarine went down."
To help with the deconcretion process, or the breaking off of sand, sediment, shells and corrosion, the sub is submerged in sodium hydroxide for hours at a time.
"An equivalent would be oven cleaner," Scafuri said. "It's very caustic, but we use it in low concentrations. What it does is it helps replace the chlorides, or the salts, that were absorbed by the metals of the submarine as it sat offshore. This is an essential part of the conservation process."
Scafuri said the concretion on the exterior of the submarine has been removed. Now crews are focusing their efforts inside.
"We've been actually able to calculate how small it was and how it worked," said conservator Johanna Rivera. "We can see the entire gears, how they worked together to get the submarine to dive and actually be successful in its mission."
On February 17, 1864 the H.L. Hunley became the world's first successful combat submarine by sinking the USS Housatonic. After signaling to shore that the mission had been accomplished, the submarine and crew of eight mysteriously vanished.
The work on the inside of the sub also led archeologists to new artifacts including a tooth belonging to crew-mate Frank Collins.
"This was something that didn't happen during the operation of the submarine or the life of the crewman," Scafuri said. "It's a postmortem detachment of the tooth that ended up stuck to the crank."
Archaeologists were able to connect the tooth to Collins through osteological and forensic analysis completed on his remains when they were recovered in the submarine.
"We were made aware that he had some missing teeth," Scafuri said.
Collins' remains were buried in 2004 alongside his crew-mates and others that lost their lives in the testing and development of the Hunley.
Other noteworthy discoveries included thin metal wraps wrapped around some of the cranks.
"This is something we expected to find because when you're turning an iron bar in front of you, or below you, to operate the hand crank you're going to need something to keep your hands from chaffing," Scafuri said.
"The most amazing part [is finding] something that was crumbled and full of sediment, and then getting to something that you know what it is," Rivera said. "That's pretty amazing."
The work being done on the sub is time-consuming with no set time frame for completion. However, the hope is within 10 years.
Scientists must follow a variety of steps while the deconcretion process is underway.
Tuesday through Thursday the 75,000-gallon conservation treatment tank is drained. The Hunley is then covered inch-to-inch with plastic wrap to keep it from drying out. Before entering the tank, the team gears up with protective body suits, goggles, and respirators to protect them from dust and chemicals. At the end of the day, the process is reversed, ensuring that the submarine remains wet at all times until the tank if filled up again for the night.
"We are moving slowly, but we are moving," Rivera said. "The extent of the site preparation and then limited time windows to work on the sub can be frustrating at times. Still, at the end of the day, the safety of the team and the submarine must always come first."
Throughout the work on the sub, the crew stays curled up in various awkward positions for hours working in the small crew compartment. Scientists use pneumatic chisels and small hand tools to remove the concretion.
Once all of the conservation efforts on the submarine are completed, the goal is to put all of the artifacts and the Hunley itself on display for the public.
Lost for over a century, the Hunley was located in 1995 by Clive Cussler's National Underwater and Marine Agency (NUMA). The submarine was raised in 2000 and delivered to the Warren Lasch Conservation Center where conservation efforts have been going on since.
The Hunley Project is conducted through a partnership with the Clemson University Restoration Institute, South Carolina Hunley Commission, Naval History and Heritage Command, and Friends of the Hunley.