A NEW METHOD FOR ANALYSING THE SEAKEEPING OF MULTI-HULL SHIPS

A three-dimensional Rankine panel method is employed to investigate the wave patterns and motions for multi-hulled ships travelling with forward speed though head sea. The steady and time-harmonic wave patterns, as well as the forces and motions in heave and pitch, are studied for a catamaran. Trailing vortex sheets, arising from the interaction of the multiple hulls, were found to be important for the continuity of the wave pattern but unimportant for the integrated vertical forces and motions. The analysis of the wave pattern allows determination of wave amplitudes which provide design constraints for the overhang structure. The analysis of forces and motions affords an understanding of the seakeeping properties and the hydrodynamic structural loads associated with multihulled ships.