Abstract
Ship steering and manoeuvring is described by a system of simultaneous equations of motion in the horizontal plane. Applying a Taylor expansion to the equations of motion produces a linear form in terms of displacement, velocity and acceleration of the ship. Research in this area revolves around the determination of the coefficients in the equations, which are usually referred to as hydrodynamic derivatives. Different methods used by different authors, to estimate these derivatives are briefly highlighted. The 3D Green's function is then adopted in a boundary integral equation method to calculate the hydrodynamic derivatives for a large tanker and a Mariner class vessel. The velocity-dependent hydrodynamic derivatives are also calculated, using the method developed by Clarke, which is based on regression analysis of experimental data. The calculations are made for both open shallow and restricted waters. The calculations are compared with published experimental results, and the comparison is shown to be, in general, good. It is concluded that estimation of the various hydrodynamic derivatives by analytical means is possible and, accordingly, reliable prediction of ship steering and manoeuvring can be made in the early stages of ship design.