Time domain assessment of vertical motions of planing hulls

Planing hull forms seakeeping assessment is a fundamental step for successful design of fast patrol boats, pleasure craft, SAR vessels where these are commonly used. Operating in high speed regime leads to hydrodynamic lift and displaced volume diminution, consequently the boat experiences the changing of trim, rise of centre of gravity and wetted surface decreases. Standard linear model, for planing hulls seakeeping assessment, based on the linear free surface condition and small changes in wetted surface are not applicable at all. This work is focused on the description and validation of a numerical code for the calculation in time domain of planing boats vertical motions. The code has been developed by the authors according to Zarnick’s theory for monohedral hull in full planning regime advancing in regular waves. The obtained numerical results have been compared with experimental data presented in Begovic et al. [1] and in Begovic et al. [2], reporting have, pitch and accelerations at CG and at bow. The comparison of numerical and experimental data is given for one model speed in wide range of tested wave frequencies.