HOW TO INCORPORATE WIND, WAVES AND OCEAN CURRENTS IN THE MARINE CRAFT EQUATIONS OF MOTION

This paper demystifies how ocean currents together with wind and wave loads influence the marine craft equations of motion. In the literature there exists great confusion of the use of absolute and relative velocity terms when modeling rigid-body and hydrodynamic forces. The article is useful for engineers who want to simulate and predict the motions of marine craft exposed to wind, wave and ocean currents as well as control engineers evaluating the performance of marine craft control systems. The results are also very useful for testing and tuning of integral action time constants for compensation of ocean current and 2nd-order wave-induced drift forces.