Giant Freeze Dryer To Preserve Ship Pieces At Texas A&M Lab

COLLEGE STATION, Aug. 31, 2010 – Texas A&M University researchers working to restore the hull of La Belle, a light frigate recovered from its underwater grave, are using an unconventional method to preserve the pieces: a state-of-the-art freeze dryer big enough to hold a few head of cattle.

La Belle was carrying 43 people when it sank in Matagorda Bay in January 1686. The ship’s remains now lie in a vat of oily preservative on Texas A&M’s Riverside Campus, the former Bryan Air Force Base that serves as headquarters for research and related activities, including a division of the Center for Maritime Archaeology and Conservation.

The massive freeze dryer, at 40 feet long with an 8-foot internal diameter, was manufactured by VirTis/SP Scientific and is the largest such machine for conservation use in the hemisphere, says Peter Fix, the maritime center’s assistant director and project conservator for the La Belle.

The instrument arrived Monday, and Fix plans to test some smaller pieces of other objects before dismantling the carefully tended timbers of La Belle and placing them in the cavernous cavity.

Freeze Dryer entrance

Freeze dryer entrance

Within three years, the hull will be reintroduced to the world, reassembled as part of a keynote exhibit in the center of the Bob Bullock Museum in Austin.

In 1996-97, researchers from Texas A&M aided in the Texas Historical Commission’s excavation of the ill-fated ship of famous French explorer Robert Cavelier, Sieur de La Salle. The recovered hull was transported for painstaking reconstruction to the Conservation Research Laboratory at the Riverside Campus.

“We will take a piece of the ship, make a mold for each piece of timber to accurately mimic the curvature of the hull, put it in the freeze dryer and in four to six months, the freeze-drying process will slowly sublimate the water from the timber,” says Fix. “It’s a much gentler process than straight dehydration, and it is slightly revolutionary in that no one has tried it before. An awful lot of engineering and understanding of the complex shapes of the ship have to be compensated for in advance of freeze-drying.”

Freeze dryerDonny Hamilton, head of the university’s anthropology department, says the new method will reduce the preservation time by about three years and cut the costs by more than a half million dollars. That’s important, because total cost of the project has risen from the initial estimate of $330,000 to more than $1.5 million. That’s largely because the cost of polyethylene glycol, a petroleum-based substance, has skyrocketed more than four-fold in recent years.

The machine cost about $500,000, but Hamilton thinks that can be recouped through future restoration projects, such as disaster recovery. “We could put in there the whole inventory of a library that has been flooded out, and bring the books back to a useful form,” he says.

After the timbers spend a few months in the freeze-dryer, they will be stored until reconstruction in the museum begins in October 2013.

“This is not only to install an exhibit, but also to demonstrate the processes of ship-building,” Fix says. “Being a nautical archaeology program we love ships, and we understand what specifically has to be done in order to have the timber emerge from the chamber in the correct form.”

Glenn P. Grieco, a research associate at Texas A&M who has built two models of La Belle, says the archaeological remains provide a case study of a little-understood vessel type and as an example of several construction techniques used in French shipyards at the end of the 17th Century.

Fix says what the researchers from the lab are doing is important on many levels.

“It’s important to everyone because it is a bit of Texas history. It’s equally important to people in France because it’s a remnant, a trace of their history,” he says. “It’s physical and tangible. You can go to a museum and you can look at this ship and you can say, ‘How did 42 or 43 people ever fit on this,’ where you may not get the same understanding if you just look at a drawing in a book.”

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About research at Texas A&M University: As one of the world’s leading research institutions, Texas A&M is in the vanguard in making significant contributions to the storehouse of knowledge, including that of science and technology. Research conducted at Texas A&M represents an annual investment of more than $582 million, which ranks third nationally for universities without a medical school, and underwrites approximately 3,500 sponsored projects. That research creates new knowledge that provides basic, fundamental and applied contributions resulting in many cases in economic benefits to the state, nation and world.

Contact: Kelli Levey, News & Information Services, at (979) 845-4645 or klevey@tamu.edu; or Peter Fix at (979) 862-7791.


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