U.S. NAVY
Marine organisms cling to the hull of USS Bonhomme Richard prior to its dry dock cleaning Dec. 2. According to Arthur A. Webb,
section head of Marine and Industrial Coatings Synthesis with the Center for Corrosion Science and Engineering at the Naval
Research Laboratory, “a fully fouled hull can result in nearly 40 percent increase in fuel consumption to maintain design speed.”
The new fouling-release paints are more expensive,
perhaps five times as much as the copper ablative coatings, and are not as durable.
“They are very smooth when applied,” McElvany
said. “But they are susceptible to scratching, which
then can provide an acceptable habitat for marine life.”
What works well for merchant ships, which are
operating just about all the time, may not be ideal for
warships, which may have extended periods in port.
“Commercial shipping and the Navy have different
operating characteristics,” he said.
The Navy is currently conducting a demonstration
with the new foul-releasing coatings. The guided-missile
cruiser USS Port Royal and guided-missile destroyer USS
Cole have the Intersleek 900 surface. Two other similar
ships have been selected to be used for comparison.
Zwitterionic Materials
ONR-sponsored research is looking at new ways to discourage marine organisms.
Fouling-release coatings have hydrophobic proper-
ties, like a drop of water in a Teflon pan that beads up
instead of spreading out. When applied to a hull, the
surface will foul, but when the ship moves the stuff
comes off. The latest fouling-release paint requires the
ship to operate at a speed of about 14 knots to slough
off the unwanted underwater guests.
