speed to be matched to vessel speed, as well. Our products are designed to polish at rates that are higher than
the fouling settlement rates and, therefore, attachment
cannot occur,” he said.
“We have also developed other self-polishing systems that are based on hydrolytically unstable functional groups, which self polish when exposed to
water,” Webb said. “Hydrolytically unstable means that
water makes it degrade and fall apart. In short, when
exposed to water, the products we have developed
decompose at the surface and, as such, the surface
ablates [erodes] away. This action is similar to the traditional self-polishing anti-fouling coatings.
“Our goal is to provide the fleet with solvent-free
products in all application areas to minimize risk to
both the shipyard workers during maintenance avail-abilities and the ship’s crew when performing routine
at-sea maintenance,” Webb said.
Home Sweet Hull
If a surface seems hospitable, the animal or plant
exudes a cement-like substance that glues it to the surface, and it sends a chemical notice to fellow sea creatures that they have located a nice neighborhood.
When this biological glue cures, the animal or plant is
very difficult to remove, and by then has attracted a
burgeoning colony of neighbors.
Different organisms affix themselves and signal the
suitability of the surface to others in various ways, said
Stephen McElvany, a program officer in the Materials
Division at the Office of Naval Research (ONR).
“We want to understand how these organisms settle
and stick, and send out cues that encourage settlement,” said Julie Christodoulou, director of the
Materials Division at ONR.
If scientists can understand what makes a particular
surface attractive to a barnacle, for example, they
might be able to create a surface or a condition that
would cause a barnacle to reject that same surface.
“It’s a hard problem,” Christodoulou said. “If it was
just one organism, we could do that. But we need to
find a solution that works for every organism in every
part of the ocean, all over the world.”
Science and technology is the foundation for future
naval capabilities, and ONR is the interface between
the science and technology community and the Navy.
That is why the Navy has involved a multidisciplinary
team of researchers, from chemists to biologists, com-
puter scientists to engineers, to find a solution.
One approach is to create a slippery surface so any
marine life that sticks to the hull in port will be
dislodged by the hydrodynamic forces of the ship once
it is underway. These “self-cleaning” surfaces are
either silicone-based, which is similar to the caulking
General Dynamics NASSCO shipyard workers use high-pressure water to clean the hull of the amphibious assault
ship USS Bonhomme Richard in San Diego Dec. 2. The
ship was scheduled to be in dry dock for about four
months for an extended period of maintenance, repair
and midlife upgrades.
used for bathrooms, or Teflon, like the surface of nonstick cookware. Intersleek 900, made by International
Paint Ltd., is a fluoropolymer-based coating for ships
operating above 10 knots, and currently in use with
many ships in the U.K. Royal Navy, including the
HMS Ark Royal.