The past decade has shown a dramatic increase in the use of unmanned tethered vehicles in worldwide marine fields. These are used for inspection, debris removal and object retrieval. The RCV-

system is an example of these advanced technology vehicles. With the requirements of high maneuverability and unusual inspection, a responsive, high performance, compact vehicle was developed. The RCV-150 vehicle component system consists of the vehicle structure, the vehicle electronics, and hydraulic system which powers the thruster assemblies and the manipulator. For this vehicle, a light weight, high-response hydraulic system was developed in a very small package. The past approximate two and one half years of world-wide field activities have resulted in almost 10,000 hours of RCV-150 operations.