Hunley Finally Ready To Reveal Itself, Brian Hicks, Post And Courier, May 1, 2014.
The H.L. Hunley may not hide its secrets for much longer. Today,
scientists at the Warren Lasch Conservation Center will immerse the
Civil War-era submarine in a caustic bath of sodium hydroxide and water
to begin a long-awaited conservation process that is expected to last
about five years.
But within a few months, conservators and
archaeologists expect to get their first look at the sub's iron hull -
and it may hold clues that finally reveal why the Hunley sank off
Charleston 150 years ago. "We have been
waiting for this for years," said conservator Nestor Gonzalez.
"Everything we're doing here is to preserve the Hunley as it was and to
preserve information recorded on the sub. Now we will finally get to see
the hull."
The Hunley conservation
project is one of the most complicated in maritime history. This is the
only complete ship to ever be conserved in this fashion, and it may be
the largest artifact ever preserved with sodium hydroxide. It
will test the capabilities of one of the most advanced maritime
conservation facilities in the world. The 40-foot iron submarine is a
complex piece of machinery with hundreds of nooks and crannies that will
have to be preserved to prevent the sub from rusting away.
The
first step will be the most revealing. In the 136 years that the Hunley
lay buried beneath the Atlantic seabed, a hard layer of sand and shell
formed on the hull.
That concretion, as
scientists call it, has protected the Hunley - but it also obscured many
details of the hull. The concretion has been left on the sub since its
recovery in 2000 for protection.
Gonzalez
expects the sodium hydroxide will take only a few months to loosen the
hardened sediment enough to allow scientists to scrape it off. Scraping
could take months, even with a team of conservators working daily. Michael
Scafuri, Hunley archaeologist, said the concretion has been mapped,
photographed and recorded with 3-D imaging to make sure they have every
bit of information possible from the Hunley's protective shell.
And now they are ready to see what lies beneath."Under that concretion is the possibility of new information about the attack," Scafuri said. With
the shell and sand removed, Scafuri said scientists should learn more
about the Hunley's design and operations, and may be able to tell what
caused the submarine to sink.
The
Hunley disappeared off Sullivan's Island on Feb. 17, 1864, shortly after
it sank the Union blockader USS Housatonic by ramming a torpedo into
its flank. It was the first successful submarine attack in history, but
the mystery of what happened after has endured for a century and a half.
The
submarine was buried beneath the Atlantic seabed until 1995, when a
dive team funded by Clive Cussler discovered it less than a mile from
the Housatonic wreckage. Removing the concretion is perhaps the most anticipated step in the conservation process, but it is just the beginning.
On
Wednesday, scientists prepared the Hunley for its caustic bath and
added giant jugs to the sub's tank to help with displacement and reduce
the amount of chemicals and water needed by about 8,000 gallons. Gonzalez
said the 76,000 gallon tank will be filled with a caustic mixture that
is 99 percent water and 1 percent sodium hydroxide. That solution will
start a chemical reaction that will extract salt from the iron hull -
salt that soaked into it over a century. The solution will be changed
out periodically until all the salt has been removed from the hull.
At that point, it will be safe to display the Hunley without immersing it in water.
This
has been the conservation plan from the beginning, and scientists are
committed to it. Gonzalez and the other scientists are excited to
finally see the hull, but they are also a little worried about soaking a
unique artifact in chemicals so dangerous the entire lab has had to be
retrofitted for safety. The new safety measures are designed to protect
the sub and the scientists, and to allow the lab to remain open for
public tours. "It's like going in to your doctor for a basic procedure," Gonzalez said. "It's safe, but there's always a risk."
But
the greater risk, said Senior Conservator Paul Mardikian, is to do
nothing. The cold water and mild electrical current that have preserved
the sub for the past 14 years cannot protect it forever.
"This is the only way to remove the salt," Gonzalez said. Mardikian
said this is not just the only way to save the sub, it is the last
chance to finally answer that nagging question: Why did the Hunley sink?
Full Text and Images Link: Post And Courier, May 1, 2014