Anti fouling paint
To protect the hull of a ship, normally anti fouling paints are used. These paints are biocides, almost all varieties contain copper and/or zinc. In the long run, all these harmful substances end up in the environment.
Regulation of anti fouling paint for ship hulls is increasingly under revision. The chemical composition of anti fouling paints for pleasure craft is now so restricted that many yacht owners complain about their loss of effectiveness. Some American yacht owners take their vessel to the Caribbean to have anti fouling paints applied that are forbidden in the USA! To forbid anti fouling paints for ocean going vessels is not an option, the environmental impact due to additional CO2 emissions -given the drag of a fouled hull- could well be worse than the environmental impact of the paint itself!
The ultrasonic alternative
Using ultrasonic anti fouling on ocean going vessels is in principle very easy. After all, it is a solid surface that we want to get into vibration. A much more straightforward proposition than protecting a box cooler! The only thing needed is transducers installed on the inside of the hull at fixed distances, varying with the strength of the transducers used.
And that is exactly the issue; the inside of the hull of an ocean going vessel is covered for large parts with fuel tanks, ballast tanks, fresh water tanks, sea chests and similar objects. Hence, not accessible. Shipsonic is experimenting with heavier, waterproof transducers to increase the distance between transducers and also allow installation inside tanks.