A Simulation Method for Small Craft Harbour Models

A simulation method is presented to improve small craft harbour design by studying the behaviour of moored vessels in small craft harbours, using physical modelling in medium size wave basins, available at most laboratories. Instead of carrying the study in an agitation model with noored vessel models and built in a large wave basin at a large geometric scale, it is performed in two consecutive models of different scales, in a medium size basin. Transfer functions of vessel movements and mooring and fender forces are determined in the first model, for representative types of vessels moored alternately at a solitary berth, under simulated inside harbour conditions and for various sea states and directions. Near berth wave spectra are obtained in the second (agitation) model for sea states covering the local climate. Integration of the wave spectra with the transfer functions leads to response spectra of vessel movements and forces. Finally, maximum movements and forces are determined from the response spectra and are used together with limiting criteria and the long term wave statistics to choose the optimum configuration of: harbour layout, types of berth structures and mooring and fendering systems.