Thursday, January 15, 2015

H.L. Hunley: Scientists peeling away crust on submarine marvel at its craftsmanship

Scientists remove concretion (Photos courtesy of Friends of the Hunley)

Scientists chiseling away decades of sand and shell from the H.L. Hunley are forging a tie to the builders of the historic submarine: A painstaking attention to detail.

Since August 2014, a team of conservators using small tools, including dental chisels and hammers, have been removing concretion coating the exterior.

They are looking for clues as to why the Hunley sank after it became the first submarine to sink an enemy vessel.

“It keeps surprising us,” said Nestor Gonzalez, assistant director of Clemson University’s Warren Lasch Conservation Center in North Charleston, S.C.

You have a very close sense of the attention to detail and the care they put into it," he said. "How the rivets are perfectly flush and the finishing is very high quality.”

Three days a week, members of the team enter the drained tank, wearing protective eyewear, gloves and masks as they slowly reveal the doomed submarine’s skin.

That work is adding to their knowledge of the craftsmanship that went into the Hunley, which was built for the Confederacy in secret in Mobile, Ala., without the use of blueprints.

Scientists have been looking for any separation of the wrought iron plates that cover the exterior. Such a discovery would indicate the Hunley may have suffered fatal damage when the torpedo it planted into the hull of the Union ship USS Housatonic went off.

“We have not seen anything like that,” Gonzalez recently told the Picket. “The guy was a very good builder.”

What the team is finding is a vessel that, while corroded, retains its structural integrity. The builders staggered the plates to strengthen their hold and carefully connected the rings that form the skeleton of the 40-foot Hunley.

“Everything had been very well thought out,” said Gonzalez.

Conservator Virginie Ternisien at work 

The stuff of legends

The Confederate government brought the Hunley to Charleston in a bid to help break the Union’s siege on the port city. The eight-member crew that set out for the Housatonic knew the risks.

Five members of the first crew died in August 1863 when it accidentally dived while its hatches apparently were open. The second crew's eight members succumbed in October when the Hunley failed to return to the surface.

On the moonlit evening of Feb. 17, 1864, the crew of the hand-cranked vessel set off a charge that sent the Federal vessel to the sandy bottom outside Charleston Harbor.

The Hunley – likened to the shape of a whale -- disappeared from view. What happened to it has become the stuff of legends and research for decades.

For a long time, one prevailing view held that a lucky shot broke the glass in one of the Hunley’s portholes, bringing in rushing water and causing the sub to sink. But research has not proven that theory.

Another scenario holds that the Hunley was swamped by or struck by another Union vessel. Or that it plunged to the sea floor to avoid detection, and never made it back up. A latch on the forward conning tower was found to be not properly locked, adding to the mystery, CNN reported in a 2014 article about the project.

In January 2013, officials announced a significant discovery.

Research showed the submarine was less than 20 feet from her 135-pound torpedo when it exploded. The effects of the blast may have sent the Hunley to the bottom, where the crew ran out of oxygen.

Ongoing efforts to solve the mystery

Conservators have been looking for any holes or bullet damage that may help explain why the Hunley sank.

“There is nothing we can see at this point, said Stephanie Crette, director of the Lasch center.

The vessel appears intact.

“We are stabilizing the items, but also working to unveil the secrets of the submarine. We are moving toward finding evidence as to why it sank,” added Gonzalez. So far, there are “no new clues.”

Removing the sediment from the Hunley is a critical component in understanding its construction and what happened.

Last May, scientists immersed the submarine in a bath of toxic sodium hydroxide to help loosen the concretion. The idea is to loosen the sediment, remove as much salt as possible from the wreckage and help protect it from further corrosion.

The scientists work from about 8 a.m. to 2 p.m. on Tuesday, Wednesday and Thursdays after solution is drained from the tank and the pH level is lowered, said Crette. The tank is refilled each day when their work is completed. Analysis is done on other days. (The general public can see the Hunley on weekends).

In some areas, the concretion can be up to two inches deep. The team works in a grid fashion, first exposing the rivet line and then working their way to the center of the plates.

Next up: Hunley’s interior

Scientists have completed cleaning nearly all of the exterior plates and are moving on to cast iron components – a very long and complicated process.

“Cast iron is very difficult,” said Gonzalez. “But it is also very rewarding … We are seeing absolutely outstanding surfaces.”

Builders used cast iron for the dive planes, the conning towers and for parts of the bow and stern. Conservators are excited about exploring the connection that linked the torpedo spar to the hull. “It can reveal fantastic details,” said Gonzalez.

Officials said they have found no evidence indicating a problem with forward conning tower may have had anything to do with the Hunley’s demise.

Scientists expect to begin deconcretion of the interior in about three months, with the entire process completed by the end of the year.

While the Hunley submarine is empty, there’s a possibility that an artifact may break loose during the work, Crette told the Picket. One scientist found an entire snail shell in the encrusted exterior.

Paul Mardikian works on the bow.

With the chipping away of each piece of crust, the submarine is returning to its original appearance, the conservators guided by an 1863 painting of the Hunley by Conrad Wise Chapman.

The nonprofit Friends of the Hunley provides a history of the boat and current conservation updates on its website.

“A lookout aboard the Union Navy's largest ship was tired, cold -- but restless. Talk of a Confederate secret weapon was in and out of his thoughts. Suddenly he spotted something move in the chilly waters. A porpoise? There were certainly a lot of them around. But something about this one didn't seem right."

What didn’t seem right was the Hunley, which sank the Housatonic. Five of its crew members died; 150 others were soon rescued.

The eight men on the Hunley also died. The quest continues for the manner and cause of their deaths.

(Photos courtesy of Friends of the Hunley)


  1. I am pleased by an inordinately high number of page views on this item, linked by a certain Facebook page. Can anyone please tell me what the page might be? Cheers

    1. Also dr. Kara Cooney the famed egyptologist linked to this article from her FB page.

    2. page i used to get here is Confederate States Of America

    3. Wrecked & Abandoned Aircraft,ships and subs

      C. Mark Sublette
      Clemson, S.C.

    4. THURSDAY, JANUARY 15, 2015
      on Facebook

    5. also by Got Dolphins? for those of us who are submarine qualified.


    7. It's a Facebook page called "I F*cking Love Science". They link articles from many scientific fields every day, and have a huge following amongst

    8. It's probably getting a number of hits from Facebook pages relating to submarine sailors and vets. I found the link in a closed group called "The Submariner's Mid-watch", but had also seen it on a couple of other similar groups.

    9. The US Navy's "Undersea Warfare" FB page.

    10. I saw the link to this blog on a FB post by Shiloh National Military Park.

      Good stuff

    11. has a facebook site where I found the link.

    12. has a facebook site where I found the link.


  3. I actually went to Charleston just to see her. It's a very worthy project.

  4. Confederate States of America Facebook page.

  5. I discovered the Hunley in 1970 and, in 1995, at the official request of the South Carolina Hunley Commission I donated my rights to the wreck to the state so it could be raised and preserved. Read more about it at

    1. See also Michael Bear's interview of me in California Diver Magazine, in which I answer questions about my 1970 discovery of the Hunley and fiction writer Clive Cussler's absurd claim in 1995 to have discovered her. Here is the link

  6. I think I found it on an a New York editor's page. Which means it's being shared. I shared it too, by the way. Great post, interesting history.

  7. After the vessel was retrieved a dear friend of mine with the SCV participated in the late confederate burial of the crew that operated the Hunley. This is a great post!

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  9. I just viewed this article via the Essex Shipbuilding Museum, Essex, MA.

  10. We saw the article on the Facebook page of the Quality Inn at General Lee's Headquarters (Gettysburg):

  11. Outstanding project I am so glad to see it progressing so well. I must take the short drive to Charleston to see the Hunley.

  12. This comment has been removed by the author.

  13. This was posted on Facebook's "Gettysburg: Past & Present". It has over 5,600 members; that might explain some of the hits!

  14. A fellow submariner posted this link which is how I found out about this page. Turns out the US Submarine community as a whole is very interested in the work you guys are doing. Keep up the great work.

  15. Dr. Lee Spence Facebook ... Hunley Finder

  16. Great article. A FB friend linked to your article.

  17. It was posted on the Facebook page of The Saber and Scroll, the history society of the American Public University System.

  18. It's interesting that the article/blog fails to mention the crewmembers remains were found at their stations, seeming seated calmly in normal positions and not in a mad scramble for their only exit.

  19. Being an ex submariner I find all info on the Hunley quite interesting. I have visited the restoration site twice. While on a visit to Ft. Sumnter, I was talking to one of the guides about the Hunley. His thoughts were that the charge that sank the Housatonic knocked the crew unconscious. They died of asphyxiation before awakening and ventilating the boat.The outgoing tide the carried her miles the opposite direction of where the experts thought she should be.

  20. From US Coastal Hwy 17 Facebook page.

  21. Proud to have been with my stepson as part of the honor guard for James Wicks from N.C. during the reenturement service of the Hunley crew. Just so happened we were there representing the 47th.N.C. reenactors. Things memories are made of.