A Consideration on Simplified Method for Calculating Maneuvering Hydrodynamic Force Derivatives in Shallow Water : Hydrodynamic Force on Ship in Turning

A simplified method to predict the maneuvering hydrodynamic forces in shallow water has been developed by Hirano and others. In the method. a ship hull is replaced by a single discrete vortex and shallow water effect on the hydrodynamic forces is expressed by using infinite images of the vortex. In the previous report, influence of the position of the single vortex on hydrodynamic forces evaluated for a ship moving obliquely was examined. In the present report, similar treatment is made for hydrodynamic forces on a turning ship. Here, characteristics of the position of the single vortex and the position where the boundary condition is satisfied are presented. It should be noticed that the characteristics for a ship in turning differ greatly from those for the ship moving obliquely.