Researchers are finally getting to see the actual hull surface of the Confederate submarine H.L. Hunley as conservators systematically and very carefully remove concretion that accumulated during the 136 years the vessel spent underwater before it was recovered in 2000.

After soaking for three months in 55,000 gallons of sodium hydroxide to loosen the sand, sediment and rust that comprises the concretion, conservators began carefully probing the outside of the hull in early August. 

They began by digging 5-inch wide “trenches” through the concretion along the length of the hull on the starboard and port sides, according to Nestor Gonzalez. He is project leader and assistant director of Clemson University’s Warren Lasch Conservation Center, home to the submarine.