Numerical Prediction of High Speed Catamaran Behaviour in Waves

The proposed paper examines the application of a boundary element method for seakeeping computation to catamaran hulls at different separations. After a brief presentation of the methodology, which is based on Rankine sources into the frequency domain, the vertical motions and the added resistance are computed, for a combination of Froude numbers and hull separations in regular head waves. Also the single demihull case is considered. The catamaran investigated in this study was derived from the NPL series by Insel and Molland (1992). A quite comprehensive set of experimental data for seakeeping have been further published by Molland et al. (2000). In addition to evident validation purposes in terms of motion response amplitude operators and added resistance results, emphasis is posed in discussing the particular problem of the effects of interference caused by the reciprocal position of the demi-hulls into the various hydrodynamic problems. To this aim, comparisons at different separations of demihulls are performed for added mass, damping coefficients and exciting forces.