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Conservators working on the 120-ton turret of the USS Monitor will take a core sample from 8-inch-thick wrought iron plating on Wednesday, Jan. 31, to find out just how difficult their job will be to complete the conservation of the historic artifact.

Among the questions they hope to answer is one that dates to 1862: In the rush to build the ironclad vessel near the start of the Civil War, did shipbuilders in Brooklyn leave out a rust treatment that would have been common in the 19th century?

If so, Old Dominion University physicist Desmond Cook, a corrosion expert who is part of the conservation team, expects to find trouble between the eight, one-inch plates that were bolted together to form the shell of the armored turret. The Monitor sank in December 1862 and the turret was not raised until 2002, so the famous, above-water portion of the vessel had 140 years of exposure to Atlantic Ocean saltwater at its wreck site off the North Carolina Outer Banks.

Chloride diffusion into the metal where the plates meet would be very difficult to remedy, even with a decade of soaking in a solution that conservators use to remove salts, said Cook. The turret, which is at The Mariners' Museum in Newport News, where the USS Monitor Center is being readied for its March opening, is stored now in a tank containing the solution.

Even tiny amounts of chlorides remaining between the plates could severely damage the relic once it is on display in the open air, according to Cook.

Perhaps the best news the conservators could get would involve a "white lead" rust treatment that was used in the mid-1800s and is similar to the lead paint that was commonly used through most of the 20th century.

"We know the Monitor was built in a hurry-140 days-and the question is, Did they put the white lead between the plates?" Cook said. He described the treatment as pasty, or grease-like. "If they used the treatment, we could find shiny, new-looking metal," the physicist said.

The task of cutting the core sample-to check on shipbuilding practices of the 1800s-is being left to present-day shipbuilders at the Northrop Grumman Newport News yard. "They're the experts who have been doing the heavy lifting on the Monitor project," Cook said. "They're used to cutting through thick metal."

Initial pilot holes were drilled in the iron on Tuesday, Jan. 30, the Monitor's 145th birthday.

The sample cut on Wednesday could be completed in four hours, but it may take all day, Cook said. "We have to go slow. We can't overheat the metal."

Once extracted, the core sample will be placed in a cylinder filled with deoxygenated water and Cook will take the historic chunk of iron to his laboratory at ODU. He said his metal and spectroscopic examination will take one month to complete.

Cook and other conservators have done tests on scraps of metal found inside and near the wreckage, but the core sample will be the first piece of the intact vessel to be cut away for scientific research. "We're treating it as a historic event," he said.

A video crew from the National Oceanic and Atmospheric Administration (NOAA), which is funding the Monitor conservation effort, will record the sample taking for the agency's archives.

If chlorides have diffused into the plates where their surfaces meet, the conservators may be forced into the time-consuming and expensive process of taking the turret apart and cleaning each plate separately. This strategy could involve a new "critical fluid" process that Cook has been working with recently. Pieces of metal can be placed in a pressurized chamber where water and other fluids under high pressure, and sometimes high heat, are used to remove harmful chemicals. Cook likens the chambers to the typical kitchen pressure cooker.

Cook, who for two decades has been a rust-buster working on troublesome rust
problems affecting bridges and other steel structures, said with critical fluids chambers big enough for the job, conservators could treat salvaged pieces of the Monitor in only a few days instead of years required by conventional methods.

Little scientific research has been done on corrosion of wrought iron and cast iron, both of which are prominent in the makeup of the Monitor artifacts. With the Monitor project being hailed as the most important salvage effort ever of a sunken battleship, scientists and conservators are under a lot of pressure to design and implement a fail-safe conservation strategy, Cook said.

As it happened, the Monitor recovery effort over the last decade has coincided with a similar effort for another Civil War vessel, the Confederate submarine H.L. Hunley. It is also constructed of wrought and cast iron and presents similar conservation challenges. The 40-foot Hunley, which sank at the entrance of the Charleston, S.C., harbor in 1864 and was raised in 2000, is at the Warren Lasch Conservation Center in Charleston.

Scientists from Clemson University took on the challenge of helping to conserve the Hunley and it was their innovation to employ critical fluid technology. Cook and colleagues at Clemson have now combined their efforts in order to assist both conservation projects.

The Mariners' Museum will open its $30 million USS Monitor Center in March. Its attractions will include some conserved artifacts, but most of the recovered material will be on view only in the conservators' water tanks. The center, however, does feature a replica of the Monitor that visitors will be able to tour.

Two canons, the propeller and steam engine also have been recovered from the wreck site. Cook said the engine, which is made of several different metals, will be the most difficult to conserve.

The conservation effort and the raising of other Monitor artifacts will be hastened, Cook said, only if new technologies show superior results. "But getting scientists involved in the conservation programs is difficult, probably because of the poor track record of funding availability in this area," he added. "Conservation is typically not a topic of scientific research. Our partnership of ODU and Clemson researchers, together with The Mariners' Museum and the Friends of the Hunley organization, is a very new mindset in the conservation area."

The Union battleship Monitor was discovered in 1973 about 240 feet below the surface of the Atlantic Ocean. It had sunk in a storm in December 1862, just a few months after its historic, indecisive battle with the ironclad CSS Virginia (formerly the Merrimack) in Hampton Roads. (The Confederates ran the Virginia aground and destroyed it so it would not fall into enemy hands.)

What schoolchildren come to know as the Civil War battle of the Monitor and the Merrimack signaled a shift in battleship construction from wood and sail to iron and steam. The Monitor also was the first navy vessel to have a turret allowing 360-degree cover by its guns.

This article was posted on: January 31, 2007

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