Sunday, December 10, 2000
By BRIAN HICKS
Of The Post and Courier staff
After months of excruciatingly detailed study and high-tech laser
mapping of the Hunley's hull, scientists are getting ready to unlock the last secrets of
the Confederate submarine.
That is, once they decide the best way to unlock the sub.
Treating the Hunley as a hospital patient, the scientists have
the 137-year-old artifact practically frozen in time as they plan its excavation. In its
tank in the Warren Lasch Conservation Center, corrosion of the submarine has been stopped
without the use of chemicals.
"Goldfish could live quite happily in this tank,"
Senior Conservator Paul Mardikian said Friday. "The corrosion has almost stopped - it
is better protected than it was at the site."
The Hunley Commission has announced Jan. 22 as the date
scientists will begin excavation of the submarine, but that most likely will be the start
of the investigation of the hole on the submarine's starboard stern.
That hole, big enough to get your arm in, will provide scientists
a clue to the submarine's construction and the way its rivets are attached inside the
hull. It opens into the sub's aft ballast tank, but will not give the scientists access to
the part of the sub where the human remains may be.
"We could open it in an hour if we wanted to, but we want to
do it in the best way possible," Mardikian said. "We decided let's look in the
stern hole, it just makes sense."
The team of scientists and archaeologists still are discussing
which way they will go into the submarine. Maria Jacobsen, the archaeologist who will
excavate the sub's interior, said the submarine is constructed of half-panels instead of
quarter panels, which was originally thought.
Basically, that means the sub is two halves split down the
middle. To remove a single plate could dump the sediment - and potentially, artifacts -
into the submarine's holding tank.
If the artifacts are moved or disturbed, they lose context - and
become almost worthless. In archaeology, the placement of artifacts tells the stories.
That has some scientists thinking that perhaps a cross-section
should be cut into the submarine for the excavation. It could be the best way to ensure
that the Hunley's history is interpreted correctly.
For the most part, scientists have tried to avoid cutting the
submarine, but some scientists believe it might actually be less destructive than removing
a panel. Removing a half-panel of the sub's hull could weaken it more than scientists
believe is safe. Mardikian says cutting the hull is merely a possibility at this point.
One thing scientists likely won't be doing is removing a conning
tower. They're made of cast iron and Mardikian says they are so brittle they could crumble
like sugar if manhandled too much.
The Hunley scientists are continuing the trend begun in the
recovery of working through every option before deciding. The plan for excavation, which
is coming together, is still fluid.
"We only get one chance to do it right," said Harry
Pecorelli, an archaeologist and diver with the project. "The recovery was so
successful because so much planning went into it."
When the scientists decide to crack through the concretion on the
hull and go into the vessel, they will not do so without the means to recreate the
submarine in exact detail.
For months, using laser technology and a high frequency
transducer, they have mapped the hull to an accuracy within a millimeter. The computer
images of the submarine are as vivid as photographs, and show the exact placement of
barnacles on the hull. Forever, they say, they will have a record of what the submarine
looked like, what condition it was in, when it was raised.
The mapping has revealed the tight quarters of the sub's
interior. The hull is 1.0887 meters wide - a little less than 43 inches. Jacobsen said the
laser mapping eventually could be the schematic for building a model of the submarine to
test its abilities. For now, however, it has sped up the process of archaeology. Instead
of climbing all over the hull with tape measures, scientists have used lasers to determine
the Hunley's exact measurements.
"With this project, we are taking archaeology into the 21st
century," Jacobsen said.
