Passive anti-roll tanks have been used for a long time in ships to damp their roll motion. The coupled roll motion response of a single degree of freedom (SDOF) system to which a passive anti-roll tank has been attached is considered in the present paper. The performance of the anti-roll tank has been studied both experimentally and numerically, with weakly compressible SPH. The sloshing flows inside the tank comprise the onset of breaking waves. In order to characterise the wave breaking effects on the response curves, tests have been performed with liquids of different viscosity, the increasing viscosity preventing the onset of breaking waves. The capabilities of SPH to treat this coupling problem are assessed and the results show that SPH is able to capture a part of the physics involved in the addressed phenomena but further work remains still to be done.
