If the H.L. Hunley has any secrets left, they are about to be exposed.

Tuesday, scientists at the Warren Lasch Conservation Center will begin scraping away the sand and shell that has covered and encased the Civil War submarine's hull for more than a century.

Beneath that crust, which conservators call concretion, archaeologists will finally get to see the real Hunley. For the first time, modern scientists will be able to examine the sub's actual skin.

"Nobody has seen the hull since it left on its mission," said Stephanie Crette, conservation center director.

And the hull, scientists hope, may contain clues that will help solve the mystery of why the Hunley never returned.

The Hunley sank in 1864, shortly after it sank the USS Housatonic. In the 136 years it spent at the bottom of the Atlantic, sand and sediment and shell accumulated on the hull, eventually hardening like a shell around the iron.

In places, the concretion is a quarter-inch thick; in others perhaps as much as a couple of inches. It has masked many features of the first submarine to sink a ship in battle.

"Even now, we don't know how some of the hull plates are connected," said Nestor Gonzalez, associate director of the conservation center. "We have been waiting for this a long time. We will know if there was any damage to the submarine pre-sinking or post-sinking."

Although the concretion has to be removed so the iron hull can be preserved, the bigger draw to scientists is the mysteries this process could uncover.

While the concretion was left on the submarine to help preserve it in the 14 years since it was raised, it has also made it nearly impossible to determine why the Hunley sank.

To read the complete article, see:Scientists to begin exposing the "real" Hunley(www.postandcourier.com/article/20140812/PC16/140819871/1177)

To read an earlier E-Sylum article, see:150TH ANNIVERSARY OF THE SINKING OF THE HUNLEY(www.coinbooks.org/esylum_v17n08a14.html)