Evaluation of Resistance and Propulsion Performance by Shallow water Tests and Powering in Shallow Water

Abstract

When a ship is carried out speed/power trials in shallow water, the measured power is larger than that in deep water. To correct the effect the method is recommended by ITTC and standardized by ISO.

In ITTC a method by Raven, which corrects viscous resistance considering the squat effect is proposed to alter the method by Lackenby which corrects the speed.

In order to evaluate the shallow water performance, resistance and propulsion tests were carried out using a tank which can perform the tests in both deep and shallow waters. The engine power estimated by the results of the tank tests, Lackenby method and Raven method have been compared and evaluated.

From the evaluation it is clarified that Raven method shows lower engine power than Lackenby method and can be applied for the shallow water correction by means of conservative correction.