World’s First Combat Submarine Original Surface Uncovered

The Hunley has finally come out of her shell. For the first time in over a century, you can actually see the original surface of the world’s first successful combat submarine. Until recently, the Hunley was completely encased in concretion, an encrusted layer of sand, sediment and shells that built up slowly over time while she was lost at sea. This material is being removed so that the conservation treatment can be completed with the hopes of ensuring the historic submarine is preserved for generations to come.

Clemson University conservators have been chiseling away this encrustation, allowing the submarine to be fully visible. During this year long process, they carefully removed approximately 1,200 pounds of concretion, roughly the same weight as a grand piano. Removing the concretion is a painstaking task with one slip-of-the-hand potentially damaging an irreplaceable artifact. Conservators have been using small hand tools, drills, and chisels to break away the concretion, which in some places is harder than the corroded iron it covers.

With the exterior now completely exposed, conservators are starting this week to remove the material covering the inside of the crew compartment. With roughly a four-foot diameter, the cramped space within the Hunley will present a new set of challenges. “It is a daunting task to do this slow, detailed work in such a small space. I can’t even imagine how intimidating it must have been for the men who actually cranked the submarine,” said Clemson University Conservator and Collections Manager Johanna Rivera.

Stripping away the material covering the submarine’s exterior is opening up an entire new avenue of study for archaeologists working to solve one of the 19th century’s greatest maritime mysteries: why did the Hunley vanish after sinking the USS Housatonic in 1864? Now they are attempting to read what the submarine’s original surface has to tell them. “Though the Hunley was successful in her attack, she did ultimately sink. To understand what happened that night, we need to determine what worked and what possibly did not go according to plan.” said Clemson University Archaeologist Michael Scafuri.

They have already uncovered holes, scratches, damage, and other curious items that will require further research to understand their significance to the submarine’s story. At this point, perhaps the most notable “forensic hot spot”— indicating a potentially evidence-rich area on the submarine – is what has been uncovered in the area of the Hunley’s weapon delivery system. Damage has been found in the area on the bow where it was mounted that may have been caused by collision or impact.

After two separate sinkings during test missions in 1863, historical records indicate that the crew likely had less than four months to completely change their mode of attack after the original towed torpedo design had been deemed too dangerous by the head of Confederate forces in Charleston. They quickly installed a spar-mounted torpedo, which may not have had a chance to be fully tested. A number of alterations are now visible in this area, confirming that some make-shift modifications took place. Archaeologists have uncovered remnants of the exploded torpedo casing still attached to the spar as well as damage to the two bolts and u-shaped clamps of the upper boom that helped hold it in place. It appears a collision or impact completely tore one of the clamps out, creating a break in the forward edge of the submarine’s bow.

As archaeologists investigate the new clues uncovered by the deconcretion, conservators will take their work into the crew compartment, hopefully uncovering more artifacts and other critical information. While the work is being done, the team constantly monitors the submarine to prevent and control corrosion as much as possible. This is a challenging task given the fragility of the cast and wrought iron structure. The Hunley was lost at sea for one-hundred- thirty-six years. During that time, salts infiltrated her iron skin and are like poison to metal. If left in open air for too long, the submarine is at risk for rapid rust, corrosion, and eventual disintegration. Usually, the submarine sits in a 75,000-gallon tank filled with a chemical treatment solution. This means conservators can only work in short intervals, wearing face masks and protective gear, while keeping the submarine wrapped in plastic to prevent too much air exposure.

Though the effort to remove the concretion is a stressful and challenging time for the submarine and her modern-day crew, it is a necessary step for the survival of one of the nation’s most treasured maritime artifacts. Also, it may ultimately provide the final clues needed to reconstruct the series of events that led to both the Hunley’s naval achievement and subsequent demise.

The Hunley Project
On the evening of 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 her crew of eight mysteriously vanished. Lost at sea for over a century, the Hunley was located in 1995 by Clive Cussler’s National Underwater and Marine Agency (NUMA). The innovative hand-cranked vessel was raised in 2000 and delivered to the Warren Lasch Conservation Center, where an international team of scientists are at work to conserve the submarine for future generations and piece together clues to solve the mystery of her disappearance. 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.