The studies of interaction wave-ship, ship motion and ship's body response, have been devoted widely. On the other hand, nonlinear free surface effects become important consideration under conditions large motion, extreme wave load and deformable elastic structure. The nonlinear free surface flows is difficult because it is a complex problem to keep the sharpness of the air-water interface tolerable and to handle moving free surface and solid boundary. On the contrary, it often involves unsteady fragmentation and merging processes. The studies which is into this book concerns primarily on numerical method developed, coupled Eulerian scheme with Lagragian particle, to capable compute with high accuracy and nonlinear effect for problems of fluid structure interaction with nonlinear free surface flows in marine engineering field. Therefore, the object of the study is emphasized on evaluation of ship performance under interaction wave-ship with nonlinear free surface flows using the coupled Eulerian scheme with Lagragian particle.