Leisure boats market has constantly grown during the recent years, entailing an increasing need of design tools. This seems particularly urgent for seakeeping and hydrodynamic performance prediction in the field of planing boats. Numerical methodologies are almost consolidated instruments for conventional displacement ships, while some shortcomings are still to be faced and overcome concerning planing craft, due to the high complexity of the hydrodynamic problem. The present paper describes a simplified methodology for the prediction of pitch, heave and roll motions of a planing boat, in regular and irregular waves. In the formulation, a 2D approach is adopted, based on ‘momentum theory’; various aspects of the wedge-theory are used in order to model the sectional characteristics, with particular attention to the added mass. A validation of the proposed methodology concerning vertical motions is presented against data available in literature.
