Barnacles, algae and other marine biofilm can reduce a ship’s fuel efficiency by up to 40%, and the U.S. Navy is working on a way to keep its hulls clean without using expensive chemicals. Up to now, the Navy has been relying on biocides to keep the pesky hitchhikers at bay. On top of harming marine life, the chemical regime is not ideal for keeping high-performance warships operating at peak efficiency. The Navy estimates that it spends an extra one billion dollars yearly on chemical biocides and extra fuel, so in addition to pure environmental altruism there are significant tactical and bottom-line incentive to find a better way to prevent biofouling. In what can only be described as poetic justice, naval researchers are turning to the marine environment itself to find safe, effective solutions to the problem.
U.S. Navy Explores Safe, Natural Biocide Tactics
The Navy is pursuing at least two different paths to sustainable biocides. Researchers at the University of Florida are working with Sharklet, a biomimicry technology based on the texture of shark skin. At the University of Washington, the focus is on preventive coatings that incorporate zwitterionic compounds. These are molecules that carry a mixed positive and negative charge, which repels microorganisms. Both Sharklet and the zwitterionic coating have a significant side benefits, which are to help prevent the transportation of invasive species and to help prevent bacterial contamination.
The U.S. Navy and Sustainability
The focus on sustainable coatings is one of those simple concepts that could yield great returns, not only for the U.S. Navy but for global shipping. As a parallel example, Energy Secretary Steven Chu has been promoting another kind of coating, white roofs, as a simple yet effective means to achieve a significant reduction in the carbon-heavy heat island effect caused by dark asphalt or tar roofs. The anti-biofouling coatings are part of the Navy’s comprehensive materials improvement program, which in turn is just one element in an overall sustainability campaign that includes such innovations as wave energy and a DARPA-developed LED lighting system. It’s not exactly a return to the ultimate in marine sustainability – wind powered ships – but it’s a big step in the right direction.
Image: UNC-CFC-USFK on flickr.com.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.