Abstract: Fouling of a ship's hull is inhibited by an amine of the formula ##STR1## where R.sup.1 is a monovalent hydrocarbon group derived from a diterpene and R.sup.2 and R.sup.3 are each independently hydrogen, an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 12 carbon atoms. The amine acts as a paint binder and as a marine biocide. An antifouling coating composition may comprise a pigment with the said amine as binder. Alternatively an antifouling coating composition comprises as binder an acid-functional polymer whose acid groups are blocked by a monoamine group which forms an organic-solvent-soluble salt of the polymer.