The U.S. Navy may have developed a solution to hull-dwelling barnacles and slime--a "foul" problem that has plagued sailors and their ships since Noah launched the ark.
The Office of Naval Research (ONR) has developed what looks like a combination pressure washer/minisub called the Hull Bio-inspired Underwater Grooming, or Hull BUG. It's designed to prevent or suppress the growth and build-up of nuisance marine growths such as barnacles--also known as biofouling (PDF).
This could be a major breakthrough. High-performance warships and submarines rely on a clean hull for speedy acceleration and hydroacoustic stealth--things that crustaceans easily impede.
Enter the Hull BUG. It's an autonomous, tether-free vehicle similar to an advanced pool cleaner. It uses four wheels and a negative pressure Vortex Regenerative Fluid Movement assembly to attach itself to the hull, where it deploys a variety of "grooming" tools, including rotary brushes and specialized water jets to groom and maintain ship hull surfaces.
It carries a suite of onboard sensors to provide obstacle avoidance, path planning, and navigation capabilities that include detection of fouled and groomed surfaces, according to ONR. Add weapons, and you also have a "force protection" vehicle.
Biofouling can reduce a vessel speeds by 10 percent and add 40 percent in increased fuel consumption in order to compensate for the added drag. In fact, biofouling on ships translates into roughly $500 million in extra fuel and maintenance costs annually, according to the Naval Surface Warfare Center's Carderock Division.