Sloshing is the phenomenon by which a moving fluid in a tank generates dynamic loads over the structure of the walls. It is a highly nonlinear phenomenon appearing in all marine structures containing liquids and is thus a problem of relative importance in the design of marine structures in general but the effects of sloshing loads are of great importance when designing LNG and FPSO tankers. The increasing traffic of LNG tankers and its growing capacities have lead to the need to accurately predict the loads acting on the structure by using valid methods for the estimation of sloshing effects. The importance of sloshing for these kinds of ships is related to the dimensions of the tanks, their distance to the centre of gravity, the filling level and the height of the ship itself. These parameters influence how the fluid in the tank will respond to an external excitation of the ship. This is an issue of concern in floating LNG units, if they are moving around massively in adverse sea conditions, especially in the cryogenic heat exchangers where it is necessary to make sure that the distribution of the fluid over the outside of the tubes or channels is even