A paint used to protect against the accumulation of barnacles etc. on underwater surfaces WordNet 3.0 & Open English WordNet

Anti-fouling paint is a specialized category of coatings applied as the outer layer to the hull of a ship or boat, to slow the growth of and facilitate detachment of subaquatic organisms that attach to the hull and can affect a vessel's performance and durability. Wikipedia

Specialist paint that greatly inhibits bio-fouling Wikidata