Analysis of antifouling paints using drum test apparatus

Abstract

Ship has been recognized as a major factor in introduction of non-native and harmful organisms which causes deleterious effects on the performance of the vessel. More than 70% of Invasive species worldwide have found to be due to hull fouling. To mitigate fouling, underwater parts of the vessels are coated with antifouling paints. Antifouling paints provide foul-free hulls up to a maximum of 95 % of the vessels underwater area. There are a number of types of these paints but “self-polishing coatings” are predominantly preferred by the shipping industry. In these types of coatings, a thin layer of biocide containing paint (typically 2 to 5 microns/month) is leached or “polished” away. This polishing action primarily depends on the hydrodynamic surface forces on the vessels hull. The higher the fluid velocity, the higher are the polishing rate. Certain areas of the vessel such as near the bow, stern, etc experience higher fluid velocity and therefore higher polishing rates thereby resulting in premature fouling. Conversely, areas where the flow rates are considerably smaller would experience lesser polishing rates which would result in insufficient amount of biocides being delivered which would again result in premature fouling. In order to study and estimate the polishing rates of Anti Fouling paint we have designed, fabricated a rotating drum test facility .Wall shear stress are to be calculated by CFD methods