Hunley hull unstable say conservators

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  • tmsmalley
    SubCommittee Member
    • Feb 2003
    • 2376

    #1

    Hunley hull unstable say conservators

    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.
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