An investigation on the control of roll excitation in head seas with U-type stabilizing tanks

Many investigations have been conducted on the use of U tanks in the control of the roll motions in beam seas. However, very few papers have dealt with their application in the case of parametric resonance in longitudinal waves. The present paper describes a mathematical model in which the fluid motion inside a U tank is non-linearly coupled to the heave, roll and pitch motions of the ship. A transom stern small vessel, a vessel well known to be quite prone to parametric amplification is employed in the study. The results are presented in the form of limits of stability, with encounter frequency and wave amplitudes as parameters. Distinct dynamical characteristics are discussed and conclusions are drawn on the relevant parameters for the efficient control of the roll amplifications in head seas.