Lateral Sway Of The Ship Forecast

The ship motions have six degrees, if the motion of surge is ignored, it is believed pitch and heave motions are coupled, roll, sway and yaw motions are coupled. Because the lateral motion is more remarkable than longitudinal motion, and it is the main reason that governs the sink of vessels, it is most important to the study of seakeeping, it is studied and predict in this paper. While the added-mass, damping coefficient as well as exciting force and moment are the each coefficient of the lateral coupled equations that Salvesen derived by the section velocity potential. The hydrodynamics coefficients are calculated by Lewis method and finite method, and we get satisfying results by compared with the results of experiment and theoretical calculation. And Lewis method is used in the calculation of responses, because it is simple one, and then the statics of vessel swing are calculated.