Dynamic Corrosion Testing Copperlok Coating System

Fuel costs are now a major economic factor in the operation of all types of cargo ships. Fuel costs are recognized to account for no less than 50% of the total costs for operating a ship. Marine fouling of a ship's hull can significantly increase fuel consumption. Anti-fouling paints control fouling but, in general, their effectiveness decreases with time and re-painting becomes necessary, introducing another cost factor. These factors produce an incentive for the improvement of present antifouling paints and for the development of new and innovative coating systems. Copperlok is one such innovative coating. The working part of the Copperlok system comprises a metallic, copper alloy coating applied by proprietary methods. The developers "of the system recognized that the copper alloy would cause severe corrosion of steel hull if applied directly to it. Therefore, an insulating "tie coat" was developed that is applied to the hull prior to the application of the copper alloy topcoat. The testing described in this report was conducted in the Ocean City Research Corporation seawater flow channel. Tests were conducted at a seawater velocity of 30 fps over a 63-day period using test panels supplied by Copperlok. The test results showed the corrosion/erosion rate of the coating to be about two roils per year at the completion of the 63-day period. The Copperlok had no significant effect on the rate at which the underlying steel corroded at intentional coating faults when there was no metallic electrical connection between the Copperlok and the steel. When there was an electrical connection between the copper coating and steel, the steel corroded at a very rapid rate. The following report describes the tests that were conducted and presents an analysis of the results.