When the Japanese attacked Pearl Harbor on Dec. 7, 1941, more than 2,400 Americans were killed, with nearly half of those on the sunken battleship USS Arizona.
In addition to the human toll, the ecology around the Hawaiian Naval base was also devastated as thousands of gallons of fuel spilled into the water and washed up on the beaches.
With an estimated 500,000 more gallons of that fuel still submerged in the Arizona, a team of Nebraska engineers and scientists will return to Pearl Harbor next week for the 75th anniversary commemoration ceremonies. They hope the knowledge they've gained in studying the corrosion of the wreckage can also help prevent environmental hazards worldwide.
"The significance is there have been many sunken ships on the west and east coasts of America and all around the world that contain fuel oil or might be navigation hazards," said Don Johnson, a retired mechanical engineering professor who has been part of a University of Nebraska-Lincoln team studying the Arizona since 1998. He earned his doctorate in Chemical and Materials Engineering in 1968.
Johnson, with financial support from the Department of Mechanical and Materials Engineering, will travel to Hawaii for the Pearl Harbor events, Dec. 9-10. The remainder of the team – former mechanical engineering graduate students Dana Medlin and John Makinson and retired University of Nebraska chemistry professor Jim Carr – are getting support from the National Park Service, which oversees the USS Arizona Memorial.
The Nebraska team will present the findings of their study and discuss what needs to be done to protect the Arizona and the environment around it.
It's a labor of love and honor for the 89-year-old Johnson, who joined the Navy shortly after graduating from high school in 1945 and completed boot camp just three days before the end of the war with Japan.
"I didn't consider myself a full-fledged World War II veteran because the war ended before I could be shipped out to the Pacific," said Johnson, a metallurgist. "But I served in the Navy and the Army (the Corps of Engineers), and feel a sense of duty to this project."
The battleship USS Arizona sank when a bomb dropped from a Japanese airplane detonated and ignited a supply of ammunition and ordnance. The ship sank within nine minutes, killing 1,177 sailors. It also released into the harbor more than half the approximately 5,000 tons of fuel on board.
Of the many ships sunk that day, only the USS Arizona and USS Utah remain submerged. In 1962, the wreckage of the Arizona was declared a national shrine and a memorial to the Americans lost that day was built across the sunken remains of the ship. None of the remains of the sailors and Marines or the fuel still aboard have been recovered.
With the possibility of eventual structural failure and fuel leaking into the harbor, Johnson and a the UNL team have since 1999 been studying the external hull corrosion and environmental effects on the ship.
Because the interior of the ship has been relatively undisturbed and no divers have been allowed inside the wreckage since 1942, there is little knowledge of the extent of corrosion in interior spaces, some of which hold oil in overhead compartments. With advances in the technology of remote-controlled vehicles, Johnson hopes new data can be obtained to answer questions about the interior of the Arizona.
Through the knowledge gained from its research, the Nebraska team came up with a mathematical formula to estimate the corrosion rate based on the effects of water temperature, the oxygen concentration and the thickness of concretion – a build-up of organisms such as algae and barnacles – that develops on a vessel in water.
Johnson named the formula The Weins Number, after former Mechanical Engineering Professor Bill Weins, who was part of the team until his death in 2001.
"(Concretion) creates a barrier so oxygen access and resulting corrosion rate is somewhat lower. That's been a surprise because concretion accumulation has very likely contributed to extended structural integrity of the ship," Johnson said. "What we've found so far, with The Weins Number, we believe the ship should remain quite stable for the 150 to 200 years after the attack."
Johnson said he looks forward to next week's trip as a "lifelong metallurgist at heart, an engineer and a veteran."
"The fact that I could look at the Arizona and relate its history to the corrosion and some of the problems that exist out there right now has been a great experience and opportunity to serve the Park Service and other government agencies."
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