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Hunley hull unstable say conservators

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Hunley hull unstable say conservators

Postby TMSmalley » Sat Nov 11, 2006 2:18 pm

FRIDAY, NOVEMBER 10, 2006 7:23 AM

Hunley is 'unstable' but conservators have a plan

BY BRIAN HICKS The Post and Courier

The corrosive salt and underwater currents of the Atlantic Ocean
inflicted more damage on the H.L. Hunley than the Yankees ever could
have hoped to.

According to the Hunley Conservation Plan recently approved by the Navy,
the 143-year-old Civil War submarine is unstable, its cast-iron hatches,
bow and stern dangerously fragile. Its wrought-iron hull was forged from
"poor quality" materials, a confirmation of how perilously short on
resources the South was by 1863 - even secret weapons got short shrift.

Today, the Hunley's bow is damaged and might not even be the same shape
it was when the sub sank the USS Housatonic in February of 1864.

The 171-page conservation document, which conservators call a "textbook"
to restoring the Hunley, paints a dire portrait of the first successful
combat submarine's current condition. But it also offers what scientists
call a conservative plan to restore it to museum quality, while Hunley
and Clemson officials continue tests on a new method they hope could
speed their timeline.

Paul Mardikian, senior conservator on the Hunley project and an author
of the document, says the plan, which calls for soaking the submarine in
a chemical bath for three to five years, is not supposition but science.
They aren't guessing what the coming work will do for the sub, they
know.

"It's very unstable, but it's not fragile," Mardikian said. "It can
handle scientists working in it. She's been very kind to us, we've never
had any problem with it. But cast iron is my big fear."

The plans call for the submarine to be restored and ready for display by
the end of 2013, a deadline the scientists say they set themselves
without any input from politicians. What good is a museum, Mardikian
says, if there is nothing to put in it?

Until then, the submarine will undergo a lengthy series of work:

--First, engineers must do a hull analysis to determine whether the
submarine, partially on its side in a hammock for six years, can stand
up on its own keel, which will make work easier.

After that analysis, conservators will remove both ballast tank pumps,
which the report says are made of iron, rubber, copper and other
materials. Such a collection would not hold up well under the alkaline
solution that will leech the salt out of the Hunley's hull.

--Next year, scientists will remove all the concretion - hardened sand,
shell and mud - that currently protects the iron. That will afford them
a view of the Hunley's skin.

Recently, Hunley experts have concluded that strong underwater currents
whipping around the sub could have caused one or more of the three holes
in the sub's hull. Two of the holes lie along a line on the hull that
has been sanded smooth, eroding away some of the porthole rings and
conning tower hinges.

Even the sub's bow, originally considered to have been molded like an
icebreaker, could just be the ocean's sculpting work.

"There is evidence of scouring that leads us to believe the sub has been
sanded by the currents," said Sen. Glenn McConnell, chairman of the
Hunley Commission. "If you look at the sub from the bow, it seems that
one side is slightly thicker than the other."

Because of the sub's condition, and other historical considerations, the
report makes it clear scientists will not take the submarine apart to
conserve it.

"If we start disassembling it, we lose the craftsmanship of the work,"
McConnell said. "They used the best materials they had to work with at
the time, but when you look at the construction, you can tell they did
it well. That has to be preserved."

The conservation plan says "disassembly of an iron hull or artifact held
together with thousands of rivets, highly graphitized case iron
elements, and fused components raises ethical and technical issues."

Keeping the submarine in one piece narrowed the choices for
conservation. Some traditional methods for preserving one iron actually
can harm the other.

The conservation plan outlines several methods tested on rivets from the
hull plates removed to gain access to the sub's interior. Mardikian said
using actual metal from the sub was the best way to test varous methods.

The report spends much time detailing Hunley and Clemson scientists'
experiments with "subcritical water" as an alternative conservation
method, and the Navy approved plans to continue tests.

Mardikian calls the alkaline solution bath ultimately the safest, and
least expensive, method of conserving the Hunley. The sub will remain on
public view during the treatment and need little more than a daily check
from scientists as chemicals are recycled through the tank.

The state is poised to decide on a plan for Clemson University to take
over conservation of the submarine in exchange for its laboratory, which
would later become the center of a materials science research campus.

McConnell said with or without the deal, the Hunley Commission will be
able to finish conservation on the scientists' schedule.

Friday, November 10, 2006.
Tim Smalley
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