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 fol lowing sea, is experimentally analyzed. The configuration emulates a turret system and the only bifurcation parameter is the articulation (turret) pos ition. The post-critical behavior depends strongly on the wave-current inte raction and the experiments were used not only to display this fact bur als o to provide a direct verification of the wave drift damping formula derive d in [J Fluid Mech 275 (1994) 147; J Fluid Mech 313 (1996) 39]. Although re stricted to following sea, the experimental setup was able to evaluate the adequacy of the formula in predicting the coupled action of the lateral dri ft force and steady yaw moment, the two force components that apparently ha ve not been yet subjected to any experimental investigation. (C) 2001 Elsev ier Science Ltd. All rights reserved.