This paper present the development of the six d.o.f. Convertible Remotely Operated Vehicle(CROV). In mechanical system. the design specification of the structure of propulsion actuators and vehicle frame is presented. We have designed seven independent thruster and the control housing and manipulator of the controller for underwater operation. We present a control system including motion control of motors and main controller and a communication based on optical Communications method for interrelated control between the controllers and actuators. control algorithm and control system under the water.