Inhomogeneous wake fields cause serious vibration and cavitation problems. To avoid these detrimental effects, it is necessary to equalive the wake non-uniformity. It has been found possible to equalize the wake fields by means of fins, tunnels, stern-bulbs etc. In this paper, a new method to equalize the wake non-uniformity is proposed and its equalizing effects and some problems in the application of this method to ship are investigated. This method is based on effects caused by free rotaing propeller in non-uniform wake. By experiments in circulating water channel, it is shown that this method is very effective to equalize the wake non-uniformity over a large of propeller disk. So, it is expected to reduce not only surface force but also bearing force and errosion by this method.
