Editorial CommEnt
Innovative coatings
could cut fuel
use and protect
environment
advanced marine coatings being developed in the US could
lead to reduced fuel consumption and reduced emissions.
N
ew hull coatings being developed exteriors. Although effective in the short- stop that biofouling, to give the Navy the
by the Office of Naval Research term, biocides can exact a heavy environ- ability to perform at a higher level.”
(ONR) are showing promise mental burden. The biodiversity of different ocean
in reducing the build-up of crustaceans However, by studying the environment, environments also creates unique
– namely barnacles – on ships’ hulls, researchers are learning from nature how it challenges. So, across the country on the
optimizing vessel performance and beats the ‘crusty fouler’ naturally – and that West Coast, ONR is working with Dr
dramatically reducing fuel costs. is where the ONR’s investment in biofoul- Shaoyi Jiang, Boeing-Roundhill Professor
Marine growth adds weight and ing prevention technologies has made at the University of Washington, on biofoul-
increases drag, reducing a vessel’s fuel significant gains. ing prevention coatings that incorporate
efficiency. The problem for ships – partic- ‘zwitterionic’ or mixed-charge compounds.
ularly in an era of high fuel costs – is “The marine environment is very compli-
simply that ‘biofilm’ can add up to 20%
“The ultimate
cated,” said Jiang. “It is as complex as the
drag and barnacles can add more than
solution is to stop
human body.”
60%. This increases fuel consumption and Zwitterionic compounds are stable,
greenhouse gas emissions.
the barnacle
alternating between positive and negative
This being the case, ONR-sponsored
biofouling prevention coatings provide an
settlement process
charges, and easy to handle in both labora-
tory and field tests. They have shown
environmentally safe alternative for protect-
before it happens”
excellent resistance to the attachment of
ing naval ship hulls, which could also benefit biomolecules and micro-organisms. The
the commercial shipping industry. result is that naturally occurring proteins,
“The ultimate solution is to stop the On the East Coast of the USA, ONR bacteria, algae, barnacles and tubeworms
barnacle settlement process before it is funding research at the University of do not bind to this unique type of surface.
happens,” said Steve McElvany, PhD, Florida where Anthony Brennan, PhD, a Apart from reducing fuel consumption,
programme manager for ONR’s environ- professor of material science and engineer- innovative biofouling prevention systems
ment quality programme. “We are really ing, has been investigating why some such as these could help minimize the US
trying to look very far forward to get the marine animals, such as whales and sharks Navy’s ‘carbon footprint,’ reduce the risk of
ultimate solution that’s good for the US remain relatively clean. Professor Brennan transporting invasive aquatic species and
Navy and the ocean.” discovered that the unique pattern of shark prevent toxic biocides from entering the
The Naval Surface Warfare Center skin contributed to its ability to fend-off marine environment.
at Carderock estimates that biofoul- micro-organisms. Whilst both the ‘Sharklet’ and zwitte-
ing reduces vessel speed by up to 10%. With this insight, Professor Brennan rionic coating inhibit the settlement of
Vessels can require as much as a 40 per started modeling shark skin patterns in barnacles, they also inhibit the growth of
cent increase in fuel consumption to his lab. The idea led to the development bacteria. This unique attribute has applica-
counter the added drag. For the US Navy, of a new biomimetic technology called tions in hospitals and other applications
that translates into roughly US$1 billion ‘Sharklet,’ which has shown extremely in healthcare where it is critical to inhibit
dollars annual extra fuel costs and mainte- positive results inhibiting marine growth. the survival and transference of bacteria in
nance to keep ships free of barnacles, The significance of his work really hit order to protect patients from infections.
oysters, algae and other debris. home during a visit to Pearl Harbour. “I As Brennan says: “This technology spreads
Existing biofouling techniques use saw a Navy ship going by, flowing with beyond the hull of the ship … there is a
methods such as toxic coatings, or biocides, green algae,” Brennan said. “I thought, great opportunity to extend this technol-
to clear barnacle colonies from the ship that’s why we are doing this research, to ogy to the public.” WT
Warship Technology October 2009 5
WT Comment OCT09.indd 5 17/09/2009 10:09:48
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