The seakeeping performance of a typical Mediterranean fishing vessel is investigated by means of a 3D Rankine panel method, which takes into account the influence of the fully nonlinear steady wave field on the unsteady wave field. The method provides in-depth information for the steady flow characteristics, so that the influence on the unsteady wave field is numerically controlled in a simple and efficient manner. Moreover, information related to hydrodynamic forces, ship motions and unsteady wave field (diffraction wave) is obtained. The radiation condition is satisfied by the shifting technique for both inter-connected flows, i.e., steady and unsteady. The effectiveness of the numerical method in predicting the unsteady wave field with good accuracy is underlined by comparison with experimental data.
