Protection of Mooring Buoys. Part IX. Results of Eighth Rating Inspection

摘要

This is the ninth of a series of reports on the protection of mooring buoys. Thirteen buoys were given their eighth rating (after a maximum of 4-1/2 years exposure) for extent of coating deterioration, corrosion of steel, and fouling. Two other buoys had previously been removed from testing in San Diego Bay because of advanced deterioration. The coating systems on three of the buoys were in good condition, while those on 10 others showed varying degrees of moderate deterioration. Two sets of 13 steel panels each, coated with the different systems used on the buoys, were given their seventh rating inspection after 3-1/2 years of exposure. One set was exposed in San Diego Bay and the other in Port Hueneme Harbor. The condition of the coatings on both sets of panels was generally better than that of the buoy coatings, but there was a general correlation between the conditions of the two test groups. On buoys coated with antifouling paints, no detectable antifouling property remained after 20 months, but on both sets of test panels, two antifouling coatings containing copper oxide were still appreciably reducing fouling after 3-1/2 years. Patches of underwater-curing epoxy applied to buoys where localized damage to the coating had been caused by abrasion were in good condition. Some patches had been in place for 3-1/2 years. Three of the buoys were cathodically protected with zinc anodes. The underwater portions of these buoys were receiving protection from corrosion 28 months after anode installation. (Author)