An Approximate Calculation Method for Maneuvering Hydrodynamic Forces on a Ship Hull with Heel Angle

Abstract

Some numerical calculations of maneuvering hydrodynamic forces on a ship hull with heel angle are carried out by using Bollay's lifting surface theory. With the assumption of rigid free-surface, the ship body is replaced by a rectangular wing with dihedral angle. Here, the dihedral angle corresponds to heel angle of the ship body. Sources are distributed over the lifting surface to represent thickness effect of ship breadth. The source strength is determined to be proportional to slope of a distribution of ship breadth. Numerical calculation is made by changing heel angle and drift angle systematically. Calculated values are compared with the experimental results presented by Son and Nomoto. It seemes that the approximate calculation method proposed here is useful for understanding a tendency showing variation of the hydrodynamic forces with heel angle.