Thursday, July 30, 2009

CSS Alabama Cannon Conserved

Underwater Archaeologist Reunites with Civil War CannonStory Date: 7/28/2009 2:46:00 PM

From Naval History and Heritage Command Public Affairs

WASHINGTON (NNS) -- A Naval History and Heritage Command (NHHC) underwater archaeologist and conservator was recently reunited with an artifact from his university graduate work, a Civil War-era cannon from the Confederate raider CSS Alabama.

Alabama sank off Cherbourg, France June, 19, 1864, following an epic battle with the Union steam sloop-of-war Kearsarge.The 32-pound pivoting Blakely gun was raised from the CSS Alabama wreck site and sent to Texas A&M University for conservation during the summer of 2005."I was employed as a graduate student conservator at the Conservation Research Laboratory (CRL) in Texas A&M's Nautical Archaeology Program at that time and was already working on a collection of CSS Alabama artifacts previously recovered from the site," said George R. Schwarz in a recent interview."I began working on the cannon, first mechanically removing the hard encrustation that covered most of the iron surface. To do this, we used a careful combination of hammer and chisel to remove large pieces of encrustation. Afterwards, we used a pneumatic chisel to gently blast away the thinner layers of concretion until the surface of the cannon was mostly clear. In the process, we discovered a brass rear gun site that was very well-preserved."

After this initial basic cleaning Schwarz and other CRL conservators performed the electrolytic reduction (ER) conservation treatment of the rare piece of ordnance."Once the cannon is cleaned, it is placed in a large steel vat filled with an electrolyte, usually a percentage of sodium hydroxide," continued Schwarz. "A power supply feeds a low current density directly to the cannon via medium gauge wires and Mueller clips. In time, the low current density gently causes the evolution of hydrogen from below the iron surface, effectively removing the chlorides that had impregnated the iron after 130 years in seawater," continued Schwarz.

"Periodically, the chloride levels of the electrolyte are monitored, and once they reach a certain point, the cannon is removed and the electrolyte is changed. Meanwhile, the cannon is once again mechanically cleaned before being placed back inside the vat. This process continued for a period of roughly three years, until the chloride content was very low. Then, the artifact was given three baths of boiling deionized water, painted with tannic acid, and dipped in boiling microcrystalline wax to seal it from the effects of moisture and other environmental problems.

"While cleaning the bore of the cannon the conservators were surprised to discover an unfired shell still lodged inside.This shell was carefully removed by members of CRL, made inert by a Marine Corps Explosive Ordnance Disposal (EOD) team from Camp Lejuene, N.C., and subsequently conserved.

In May 2008, Schwarz began working as an archaeological conservator and manager of the NHHC Underwater Archaeology Branch Conservation Laboratory located on the historic Washington Navy Yard in Washington, D.C.Part of his duties, in addition to operating the lab, is to manage the collection of NHHC Underwater Archaeology Branch (UAB) artifacts. This includes issuing loan agreements to various museums interested in displaying U.S. Navy artifacts from underwater archaeological sites.

Currently, UAB is responsible for curating approximately 1,400 of 9,000 artifacts in its inventory. The rest are on loan to museums and other institutions for display or research. Schwarz also keeps track of U.S. Navy artifacts that are being conserved by other conservation labs, such as Texas A&M's CRL. A batch of recently conserved artifacts from CSS Alabama, including the cannon and other artifacts he had worked on, were ready to be returned to NHHC UAB Conservation Lab for curation in June 2009.

The cannon is now in the warehouse next to the Conservation Laboratory and awaits placement in the National Museum of United States Navy for exhibit."As a graduate student conservator at Texas A&M, I never imagined I would be among the recipients of the conserved cannon and other CSS Alabama artifacts I was working on at the time. When they were delivered to NHHC last month, however, I could fully appreciate the effort that was put into the conservation of these once-submerged links to our Navy's culture and history. It was worthwhile because now modern Sailors and the general public can enjoy them in their preserved state. It is one thing to be working on them in a secluded laboratory, and another altogether to see visitors' awed expressions as they imagine how these objects were used by Sailors during the American Civil War at sea," said Schwarz.

Alabama was the scourge of the American merchant fleet during a two year commerce-destroying campaign before she sank during the battle with Kearsarge. A French Navy mine-hunting ship discovered Alabama's wreckage in 1984.Since the shipwreck lies in French territorial waters, the governments of the United States and France agreed in 1989 to establish a binational project to document and protect the wreck site while working to recover and conserve artifacts.

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