Mystery Of The H.L. Hunley Sinking Is Closer To Being Solved
By Bill Bleyer
July 2005

NORTH CHARLESTON, S.C. - For more than 140 years, the demise of the H.L. Hunley has remained one of the biggest unsolved mysteries of the Civil War. But the answer may be close.

Ever since Feb. 17, 1864, when the Hunley became the first submarine to sink an enemy ship, historians and Civil War buffs have pondered what caused the Confederate vessel to sink on the night of its breakthrough success.

And sometime this year, the scientists who have been excavating, preserving and studying the Hunley since it was raised from the ocean floor outside Charleston Harbor in 2000 hope to be able to finally answer the question of why the Hunley never made it back to shore after signaling its success in sinking the U.S.S. Housatonic, which was part of a blockading squadron.

“Everybody wants to know what happened to the sub and what happened to the crew,” said Maria Jacobsen, senior archaeologist of the project which is based in the 60,000-square-foot Warren Lasch Conservation Center here. And she is confident of eventually finding the answer because she says of the Hunley that “it is as close to a true time capsule as you can get in archaeology. But it also presents its own challenges.”

In the process of trying to answer the big question, the Hunley team working in a building in a former Navy base has developed new archaeology techniques and uncovered breathtaking artifacts and even human remains that are helping to illuminate the Hunley’s surprisingly sophisticated design and fill in details of the eight men who made the last voyage.

When the study and preservation of the iron hull is completed in the next few years, the sub will become the centerpiece of a new museum planned for a site farther up the Cooper River with a hoped-for opening date of Feb. 17, 2008.

“We're closing in on it,” Glenn McConnell, president pro tempore of the South Carolina State Senate and chairman of the state's Hunley Commission, said of the answer to why the Hunley sank.

He said when analysis of the crew is completed and research shifts to the hull itself, X-rays will be taken of the valves in the ballast pumping system, which is more complex than anticipated and may have had a dual purpose.

Scientists knew the pumps were used to control the water level in the ballast tanks, which enabled the submarine to rise or dive. But the same system may have served as a bilge pump to allow the crew to remove water from inside the submarine in an emergency.

“Looking at those valves, we'll begin to understand the final moments of the Hunley,” McConnell said.

“We're doing some tests on the brains; the brains of every crew member were still there in their heads,” McConnell continued. “We did some sampling and we hope that these tests will tell us if their last five minutes were traumatic or peaceful, peaceful indicating that perhaps they had anoxia and passed out and subsequently suffocated.”

McConnell said that “all these little pieces come together to build a jigsaw puzzle that is starting to draw a picture of the final minutes of the Hunley. I think within the next 12 months we’ll pretty much know.”

There are multiple theories to explain why the Hunley sank. Some think the explosion from the charge the Hunley carried on a spar attached to her bow also damaged the submarine, allowing her to flood and settle to the bottom.

Another possibility is that as the crew cranked the shaft to turn the propeller, they used up so much air that they passed out and drowned when the sub subsequently sank. Another theory is that another Union warship, the Canandaigua, coming to the aid of the Housatonic as it sank, swamped the Hunley because its hatches were open to allow more fresh air into the hull. Or rough weather may have swamped the Hunley.

“My theory,” McConnell said, “is that she was either anchored out there [waiting for the tide to change] or had turned to come in and the water did get rough and she took on some water and she was using more oxygen than she was bringing in through the snorkels and they blacked out.”

But Jacobsen, the person who will make the actual call — with input from scientists around the world — doesn’t want to get ahead of the science and isn’t willing to offer any guess about which theory will prove accurate.

However, she says the lab work to date has allowed her to draw some conclusions.

“Whatever happened appears to have happened quite quickly,” she said in an interview by the tank where the surprisingly streamlined submarine was clearly visible along with its diving planes, three-blade propeller and pine bench where the crew sat and which retains its paint. The bench was removed subsequently.

“They were collapsed more or less where they sat,” she said. “You didn't see the guys trying to move towards the conning towers to exit. So either something happened very fast or they were not able to move.” She postulates that either the crew became unconscious from lack of oxygen or the submarine flooded so rapidly that no one could move.

Whatever caused the sinking, Jacobsen said, “there was water in the submarine quite early on. What we found was that these fellows were drowned, the bodies floated, they decomposed and slowly sank.

“The other thing I can say is that from the preliminary look at the sediment, it appears that the submarine started to fill with sediment in the bow portion of the crew compartment first.”

When the sub was recovered, there were holes in the conning tower and forward ballast tank, which is separated from the crew compartment by a bulkhead that does not go all the way to the ceiling; there is an 8.5-half inch opening. “So if you had a disturbance in one of the ballast tanks you could have water coming over the bulkhead into the crew compartment,” Jacobsen said.

When the Hunley was brought to the lab and submerged in a tank of cold saltwater to prevent further corrosion, the first phase of the work was to study the intact hull to determine the best way to open it for excavation. After six hull plates were removed, the silt that filled almost the entire interior was removed in layers so human remains and artifacts could be recovered from the crew compartment.

A forensic investigation of the crew remains combined with document research led to the identification of the eight men and even reconstruction of what their faces would have looked like by the Smithsonian Institution. The remains were then buried in Charleston last spring.

As the remains and other objects were found, a total of 3,000 items, the team photographed them and then used a number of different 3-D laser mapping technologies — for the first time in an archaeological project, Jacobsen noted — to create an image of what the interior of the submarine would have looked like at the time of the sinking."

As objects were excavated from the Hunley, they were turned over to a conservation team headed by Paul Mardikian, the senior conservator who previously worked on artifacts from the Titanic.

“My work is to ensure that nothing disappears,” he said. “After many years underwater, any material — it could be cotton, wool, wood, iron, glass — is unstable. If you let it dry out, you're going to lose not only the artifact but all the information that goes with it.”

So the tank is drained for excavation or study and then immediately refilled with seawater through which an electrical current is run to reduce corrosion.

In the meantime, Mardikian is experimenting with different techniques to determine the best way to remove the salts from all the metal so the Hunley can be displayed out of water in the future museum.

To study the sub and the artifacts, 900 X-ray photographs have been taken and stored in a computer.

Mardikian pulled one up one on the screen. It was commander Lt. George Dixon’s watch, which was recovered from a block of sediment. “What you are looking at here is the movement of the watch,” he said. “When I opened it, the hands were still in position.”

It was the X-rays that revealed that the crewmen’s brain tissue remained inside their skulls. “It was an incredible discovery,” he said, even though scientists had told the team that they would probably find soft tissue from the bodies because of the lack of oxygen inside the sub to promote decomposition.

“We also found soft tissue in the shoes,” he added. “What the human remains from the Hunley will tell us we don't know yet,” other than the crewmen’s identify, he said.

“The most striking discovery for me as a conservator was to be able to find fingerprints,” Mardikian said. “There were fingerprints in the concretion, which is the kind of cement that forms when iron corrodes underwater. What we can do with them we don't know.” But they might become useful with future technology.

Mardikian showed a shoe that is being preserved. After excavation, it was CAT-scanned at a local medical school, then the bones inside the tissue were removed, the shoe was cleaned mechanically and chemically and then freeze-dried in a large machine and that looks like a 6-foot-tall washer-dryer combination that keeps items at -42 degrees Centigrade. This removes the moisture, which would become acidic and cause the leather to crack. The whole process takes several weeks.

Everything that comes out of the submarine is labeled and saved, even pieces of the silt-iron concretion broken off during the excavation of the interior.

“We've conserved hundreds of artifacts so far like buttons, shoes, but we've got so much more to do,” he said. The conservation of the artifacts may continue for several years after the hull is preserved and displayed in the new museum.

While they wait for conservation, the objects are kept in water-filled containers in a 50-square-foot morgue enclosure in a corner of the lab is kept at -5 centigrade. That’s where the human remains were kept prior to burial at Magnolia Cemetery last spring; some samples were kept for future testing.

“At that temperature, you don't freeze and have ice crystals but it's cold enough to slow down all the enzymatic reactions and all the adverse reaction that could happen to fabrics, human tissues and fragile artifacts,” Mardikian said.

With the excavation and forensic work completed in the fall, Jacobsen said the research has moved on to studying the sediment removed in layers and in core samples.

The analysis will try the answer the questions of how the submarine filled with silt and how long the process took. “We look at radioisotopes in the different layers that have a very short half life and we can determine what the dates of those layers are. We will look at the chemistry of those layers and what does it say about the availability of oxygen at any given time. We will look at the grain sizes in the different layers if there are different layers.

“Finally, you need to look at the submarine itself,” Jacobsen said. “The submarine is obliterated from view. Every surface is covered with a corrosion product, the concretion.” Leaving the corrosion in place until the scientists were ready to study the hull itself prevented rapid deterioration of the metal because it serves as a protective layer.

“We'll have to study the hull damage that is visible and determine how did it occur,” Jacobsen said. “Was it the result of impact, explosion, corrosion underwater?”

Jacobsen said that after more than four years the thrill of coming to work on the Hunley has not dissipated. “There are so many things to understand and so many avenues of investigation on a daily basis that it's really, really exciting,” she said.