In this study, seakeeping performance of a high speed catamaran is investigated by model tests in irregular head waves. Discussions are made on the vertical motions, wet deck slamming, side hull slamming, and added resistance. Results of model tests are compared with those of numerical calculation based on the strip method and linear superposition method.
Recently, various multihull ships especially catamarans are developed as a high speed passenger ship. Seakeeping performance becomes the most important design consideration of such ships because of their high speed requirements and passenger's comfortness. Theoretical methods based on the strip method are widely used to predict the seakeepmg quality of mono-hull ships. Slight modification of the strip method to include the two-dimensional interaction effects between demi-hulls are introduced for the prediction of catamaran's seakeeping performance by many people such as Ohkusu et al.. Three-dimensional effects decrease this interaction between two demihulls, which becomes more pronounced for higher advance speed and for higher wave frequency. Attempts to include the three dimensional effects have been made by Ohkusu et al. using slender body theory, by Kring & Sclavonous using Rankine source method, and others. However, nonlinear phenomena including cross flow effects, and vortical wake effects, which induces large wetdeck slamming and large transverse loads on each hull, can not be predicted well by theoretical methods. In this study, we investigate the seakeeping performance of a catamaran m irregular head wave by experimental study using a scaled model. The tests are made in the towing tank of the Korea Research Institute of Ships and Ocean Engineering which has dimensions of 200m × 16m × 7 m. Mean added resistance is also examined for the estimation of service speed In a design seastate. Results of motion measurements are compared with the numerical calculation using strip method to see the validity of the numerical method.