Hunley's hull revealed after careful cleanup

VIDEO: Hunley's hull revealed

NORTH CHARLESTON, SC (WCSC) - South Carolina is getting its first look at the hull of a historic Civil War submarine in more than 150 years.

Scientists working to preserve the H.L. Hunley submarine have been chipping away at a layer of rock, sand and silt, often referred to as concretion, that built up over time on the hull while she rested on the ocean floor.

The concretion removed for the submarine weighs nearly 1,200 lbs, about the weight of grand piano.

They say the submarine now looks like it did when it sank a Union blockade ship Housatonic just outside Charleston Harbor on Feb. 17, 1864. After sinking the ship, the hand-cranked Hunley and its eight-man crew did not make it back to port.

While the concretion served as a protective coating, it also inhibited the effectiveness of conservation efforts needed to ensure the ship's survival.

Archaeologist Michael Scafuri says now that the submarine is uncovered they can lean more detailed information.

"It's helping us understand more about the submarine, how it functioned, how it is constructed and of course giving us more clues as to what happened and why it sank," says Scafuri.

Conservator and collections manager, Johanna Rivera says the submarine is very delicate.

"Some areas of the iron are softer than the actual concretion that is covering it," says Rivera.  "So if you cannot see where your concretion stops and when the iron starts you can really damage the hull."

The submarine was discovered in 1995 and raised then transported to a North Charleston conservation lab in 2000.

Copyright 2015 WCSC. The Associated Press contributed to this report. All rights reserved.