A system is provided for rigidly attaching a supply ship to a receiving ship to facilitate efficient transport of materials there-between even when the vessels are subject to heavy seas and weather. A telescoping truss assembly is provided on the first ship, and has a distal end configured to mate with a receptacle assembly on the second ship. Cables are disposed within the truss and are used to draw the truss and receptacle assemblies into engagement with each other. Once the assemblies are engaged, a hydraulic system is used to draw the two ships together, rigidifying the truss assembly and fixing the two ships in a "catamaran" arrangement. Subsequent transfers of materials between the ships can be carried out without the need to compensate for the relative dynamic vertical and horizontal displacements between the ships due to wind and waves.