The initial effects of immersion on the release rate of antifouling agents from ships' hull paints were investigated. Rotating cylinder tests were conducted similar to the ASTM/ISO method. Cylinders coated with sample paints were placed and rotated in containers for up to 24 hours. Concentration of leached antifouling agent was measured at specified intervals. Measurement was carried out under various conditions: pH of the solution, composition of the solution (de-ionized water, phosphate buffer solution and substituted ocean water) and the rotating speed of the cylinders. The dissolved chemical species and pH of aqueous solution significantly affected to the release rate of antifouling agent, where the degree of the effect was dependent on the composition of the antifouling paints. The release rates under rotating conditions were higher than that under static conditions, although rotating speed did not much affect the release rate under those of greater than 60 rpm.
