Prevention of Attachment of Marine Organisms on Propeller by Electrolytic Current

Many marine organisms attach to the hull and propeller surface of anchored ships. This increases the frictional resistance of the propeller and lowers its rotational frequency. Anti-fouling hull coatings prevent the attachment of fouling organisms, however they contain poisonous compounds such as organic tin and cuprous oxides. Since marine organisms cannot attach themselves to a propeller during a voyage, a safe, easy and effective method to prevent attachment during anchorage is desirable. Some propeller coatings which do not contain poisonous compounds have been examined and developed. However, the coatings do not adhere perfectly. In a preliminary experiment, it was observed that marine organisms were 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 and the technique does not pollute the marine environment.