A polyol having the formula X(O—R1—OH)m(O—R2)nHq. X is Si, C, B, Ti, P, Al, Mg, or Ca. Each R1 is derived from dipropylene glycol or tripropylene glycol, and each R2 is an aliphatic group. m is 2, 3, or 4; n is 0, 1, or 2; and q is 1 or 2 when X is C, and is 0 when X is not C. A thermoset formed by reacting a polyisocyanate with the polyol. An antifouling coating containing the thermoset and optionally a biocide. An antifouling coating that is not foam formed by reacting Si(O—R1—OH)m(O—R2)nR3 with a polyisocyanate. Each R3 is an alkyl group or aromatic group.