Abstract
Many marine organisms attach to the hull and propeller surface of anchored ships. This attachment of marine organisms increases the frictional resistance of the propeller, and lowers its rotational frequency. Although anti-fouling paints for the hull prevent the attachment of fouling organisms, they contain poisonous compounds such as organic tin and cuprous oxides.
Since marine organisms cannot attach to the propeller during voyage, safe, easy and effective method to prevent attachement in anchored ships is desirable. To date, some propeller-coating paints without the poisonous compounds have been examined and developed. However, the paints have not yet been holding perfectly. In our preliminary experiment, we observed that the marine organisms were seen attached everywhere on the test plate except the scratching part. The electrolytic current, therefore, is feasible to prevent the attachment of marine organisms to the propeller. The electric technique does not pollute the marine environment, unlike the anti-fouling paints. This techique may be useful not only to ships but also to many other structures in the ocean, such as buoys, pontoon bridges and rigs.
