There are two types of ship bottom paint: a self-consumable type that prevents the adhesion of animals and plants while the coating film itself dissolves when it is submerged in water, and a high hardness type that prevents the adhesion of animals and plants by seeping the antifouling agent between the coating films.  Consumable paints are very effective for boat mooring at sea (for antifouling properties). The high hardness type cannot take advantage of it. Since high-hardness type paint does not dissolve, unnecessary paint film tends to remain, and it is necessary to remove the previous paint with a ship bottom paint remover every time it is applied or every few years. The advantages of using high hardness paint are power boats that always run at 30 knots or more, racing yachts, diving boats, etc.