Abstract: A high speed vessel system comprises a surface-craft, a sub-craft, a pair of main foils, at least a pair of auxiliary foils, a narrow strut connecting the sub-craft with the surface-craft. The main propeller and main rudder are located at the stern end of the sub-craft hull. When the vessel system is cruising at a high speed, the surface-craft will be lifted above the water line mainly by the buoyant force of sub-craft hull. The foils will control rolling and pitching of the vessel system. The surface-craft and sub-craft will be connected by a separable ball joint (first embodiment) or a plurality of rotatable links (second embodiment) when the vessel system is in sea operation. The sub-craft can be raised up to the water surface level to minimize the draught of the vessel system when the system is resting in a harbor. The present vessel system is specifically designed for a sea going vessel of big size and large tonnage, which needs to cruise at high speed constantly.