A weathervane ship under wave and current action: an experimental verification of the wave drift damping formula

In this paper, the stability of the equilibrium of a tanker, free to rotate around a vertical axis while being displaced with constant velocity in following sea, is experimentally analyzed. The configuration emulates a turret system and the only bifurcation parameter is the articulation (turret) position. The post-critical behavior depends strongly on the wave-current interaction and the experiments were used not only to display this fact but also to provide a direct verification of the wave drift damping formula derived in [J Fluid Mech 275 (1994) 147; J Fluid Mech 313 (1996) 39]. Although restricted to following sea, the experimental setup was able to evaluate the adequacy of the formula in predicting the coupled action of the lateral drift force and steady yaw moment, the two force components that apparently have not been yet subjected to any experimental investigation.