A fast autonomous scaled ship for experimental seakeeping control studies

A second part of our research on the seakeeping control in fast ferries, is devoted to general heading and sea state conditions. Although scaled ships are basis for experimental studies, it is not possible to keep using them in towing tanks. The main reason is that high speeds require large space for experiments, so towing tanks are not large enough. This has been noticed after the first part of our research, with head seas, in a 150 m /spl times/ 30 m towing tank with wave maker. Consequently, we are preparing for open air experiments. A new fast autonomous scaled ship has been developed. She is self-propelled, and is self-governed by an embedded PC on-board. The ship carries sensors for heading, speed and seakeeping control. Several scaled moving appendages have been added: two transom flaps, two lateral fins, and a T-foil. The ship uses two scaled waterjets, which also control the heading: the ship has no rudder. A distributed monitoring and control system has been designed and implemented for on-board operation. All equipment has to be very light, since the real fast ferry that we reproduce at 1/40 scale is aluminium made. A digital radio link has been provided for distant off-shore monitoring. The paper describes the autonomous ship, the on-board monitoring and control system, and shows several experimental results with quiet waters and with several types of waves.