Abstract
To determine the loading conditions considering the action of both bending and torque moment for a passenger catamaran moving among waves, a method for calculating equivalent design waves under multiple load control parameters was derived based on wave load prediction results using three-dimensional potential flow theory. The method was developed by defining the wave amplitude discrepancy factors between the primary and second load of the combined bending and torquing equivalent design wave. The primary goal was to find a reasonable design wave. Finally, the design waves of a target passenger catamaran ship were calculated using the proposed method, and each load component of every design wave for the target hull was recalculated. The average error compared with the object load component was less than 1%, which verifies the effectiveness of the method and offers an effective engineering evaluation method for a catamaran.