Overcoating Inorganic Zinc Primers for Underwater Service

Abstract

During ship construction, steel hull plate is normally protected with an inorganic zinc preconstruction primer. For the underwater portion of the hull, conventional practice is to remove the primer by abrasive blasting before final coating of the hull. If the requirement for removing the preconstruction primer could be eliminated, there would be a significant cost savings. As a result, a laboratory study was undertaken to investigate the performance of selected marine coatings when applied over inorganic zinc primers in underwater service. In general, the results of the study suggest that there are inorganic zinc preconstruction primers that can be overcoated for underwater service. The results encourage further tests to investigate the parameters affecting compatibility.