A seagoing vessel having a length of between 45 and 175 meters and designed to operate at speeds of between 25 and 70 knots, the vessel comprising a single main hull with stabilising amahs positioned on either side, wherein the hydrostatic value of GM determined in the transverse plane lies between 0.5 and 5 meters, the vessel being shaped above the designed waterline such that the righting lever (GZ) curve as the vessel heels meets the following requirements: the area (b) bounded by the GZ curve plotted on the heeling axis between the angle of flooding and the heeling lever associated with a specific gust of wind is greater in value than the area (a) bounded by the GZ curve plotted on the heeling axis between the heeling lever associated with the specific gust of wind and an angle associated with the amount of roll of the vessel to windward under the action of the waves.
