A binder for an antifouling composition comprising a mixture of: (i) at least one organic monofunctional acid or a salt thereof; (ii) at least one organic polyfunctional acid having a molecular weight of 300 to less than 1000 or a salt thereof, e.g. a dimerised, trimerised or oligomerised fatty acid or resin acid; and (iii) at least one metal compound.
