| Johnson
50, 56 Analyzes Hull of USS Arizona
The
USS Arizona, sunk in Pearl Harbor by the Japanese in 1941, is corroded,
aging and leaking oil.
The National Park Service wants to know how the ship is holding up after
58 years beneath the sea.
The national historic landmark attracts about 1.5 million visitors
annually.
The Arizona went down with between 800,000 to 1.7 million gallons of oil
inside and although it burned for three days after the attack, no one
knows how much fuel it still holds.
Less than 2.5 gallons of oil leak from the ship each day.
In addition, 1,177 men perished in the attack and the bodies of more than
900 of them are still entombed in the ship.
To avoid a potential environmental problem if the vessel breaks up, Donald
L. Johnson Met E 50, MSc Met 56 and other researchers are trying to
determine how the sea life living in the ship and the pollutants in the
harbor are affecting the ships rate of corrosion.
Johnson, a professor emeritus from University of Nebraska who holds a
doctorate from there in chemical engineering, is part of a team of
researchers and marine archaeologists studying the problem. In October,
the researchers visited the memorial to study hull samples and presented
"USS ArizonaCorrosion, Metallurgy and X-ray Studies" at the
USS Arizona Visitor Center auditorium.
Johnson is one of the forces behind the effort to understand the state of
the Arizonas hull.
After visiting the memorial as a tourist in 1998, he convinced two young
Nebraska colleagues to join him in the study. Although the university paid
for the recent trip to Hawaii, the rest of the research is a volunteer
effort. Johnsons colleagues became certified divers this summer and
were able to inspect the wreck at close range. John-son participated via
interactive video.
"One of the important things were looking at is the thickness of
the hull after 58 years of exposure," says Johnson. "Does it
have 50 more years? I dont know if it will go that long. It may."
One problem is that the researchers dont know the hulls original
thickness. This is being researched at the national archives.
Johnson says they are now analyzing the steel used when ship construction
began in 1913 and when the ship was modernized between 1929-1931. Results
of metallographic examination and chemical analysis of these materials was
presented at the International Metallographic Society Convention Nov. 1-4.
Vertical hull surfaces are covered by an approximate 3/4 inches hard
biofouling layer, an entwined and calcified mass of oyster and vermetid
shells. X-ray studies of the metal/biofouling are now in progress to
determine how the two interact in the corrosion process.
Although the Arizona is not in imminent danger of breaking up, the
National Park Service would like to be prepared.
Johnson, together with William Weins and John Makinson of the University
of Nebraska, hopes to develop a better understanding of hull corrosion in
about 40 feet of water and 20 feet of mud and water.His research is made
possible, in part, by the University of Nebraska-Lincoln Emeriti
Association through the Maude E. Wisherd Funds.
Mines Magazine, November/December 1999
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