Full-scale propulsion measurements on a planing pleasure yacht in waves

Full scale seakeeping trials experiments are very limited, in particular for the case of leisure planing hulls. In this study, an in-depth analysis of both head and following sea trials of a 65 ft planing hull yacht in mild weather conditions is presented. The analysis deals with both propulsion and motion measurements, with particular attention on the relationships between them. Full and model scale experiments in calm water have been carried out in order to provide a baseline for seakeeping data. Both propulsion and motion datasets have been analyzed in frequency and time domain in order to provide the most comprehensive assessment of the relationships between torque response and hull motions. In the frequency domain, torque RAOs have been defined and discussed, where in the time domain, an in-depth analysis of torque response phase has been carried out. The main novelty of the present study lays in the detailed analysis of both head and following sea motion and propulsion data of a pleasure planing hull yacht, in particular the assessment of the propulsion system response phase. In addition, an ad-hoc experimental setup to measure the full-scale propeller shaft mechanical properties has been described and results are compared with initial guessing.