Underwater paints in use in the more recent years of maritime history have been used ostensibly to inhibit the growth of marine life on the underwater portions of ships and small craft. From the latter days of speedy craft in sail to modern times of super steam and diesel powered vessels mariners have been frustrated in sustained speed efforts and engineers have been prevented from obtaining maximin fuel economy by the retarding effects of weight masses of irregularly shaped marine organisms maturing on the bottoms of their ships.