Ultrasonic Antifouling Grows as ‘Green' Option for Vessel Owners

By using sound waves, ultrasonic antifouling can prevent the growth of algae, barnacles and slime on boat hulls and interiors, and can protect sea chests and box coolers as well.

- Susan Buchanan

The technology has been employed internationally from Europe to Australia, Japan, Chile and the Caribbean, and implemented on commercial, military and recreational vessels. More recently, these systems have caught on with yacht owners in North America.

Fouled, rough hulls can slow boats and increase fuel consumption, and antifouling paints — while effective — can release toxins when a vessel is in the water or when coatings are scraped off in dry dock. Usage of ultrasound has grown following the International Maritime Organization’s ban over a decade ago on organotin in bottom paints, and because of moves to limit copper as an antifouling agent. Ultrasonic systems don’t rely on chemicals that can harm fish and mammals or pollute the air, and they can reduce vessel lift outs for cleaning.

The cleaning abilities of sound waves have been recognized since before World War II. Starting in the 1950s, sound waves were utilized for this purpose in the food, agriculture, electronics, medical, aircraft and auto industries. While ultrasound’s marine applications have been acknowledged for decades, usage by commercial vessel operators has only gained traction in the past 15 years. To install a system, transducers are mounted inside a vessel’s hull, or on other internal features, along with a control box. Onboard generators or shore sources power the equipment.

“Wherever sea, river or estuary water touches a vessel or its internal equipment, biological organisms are at work, clogging pipe work, encrusting the hull and propeller, increasing fuel consumption and requiring expensive remedial work,” said Darren Rowlands, director of NRG Marine Ltd. in the United Kingdom. “Antifouling is therefore an essential preventative measure that all commercial, military or leisure operators use to maintain smooth, fouling-free surfaces to reduce running costs and extend service intervals.”