An Experimental Study on the Turning Characteristics of KCS with CG Variations

Abstract

A ship in heeled condition has a different manoeuvrability when it sails. The aim of this study was to investigate the change of turning ability of the ship with different center of gravity (CG) positions. A free running model test (FRMT) with 1/65.83 scaled KCS was conducted in three easily heeled CG conditions: up, forward, and to port. The tests for each condition, such as GM condition (up), trimmed condition (forward), and heeled condition (to port), were analyzed with trajectories and navigation data, and the test results showed that the tactical diameters became shorter in three conditions. In the case of KCS, turning ability in trimmed condition was considerably changed due to the waterplane shape of the ship. These results indicate that the roll angle of the ship strongly affects the speed and rate of turn on the ship. The trajectory and navigation data from this study provides benchmark data sets for other simulation research to compare with for maritime accident analysis.