The Augmentation in Frictional Resistance due to Slime

Abstract

Recently, remarkable improvement of anti-fouling paints has been achieved and anti-fouling effects against shells, barnacles, moss and grasses seem to be almost complete. However, slime (invisible thin film which collects on any surface in the first few days of immersion) adheres to these paint surfaces. In this paper, the effects of the slime on frictional resistance and the separation of slime by the flow are investigated by experiments of concentric cylinders, a model ship and rotating disks. By the extrapolation to actual ships from these test results, augmentation in total resistance due to slime is estimated to be about 9〜l0%, provided no separation of slime occurs.