Abstract: A sail boat propulsion and stabilisation system. The system uses a device to substantially increase the performance of sail or motor boats by reducing the displacement to increase speed and comfort during sailing, due to its light weight and dynamics. The system comprises a control panel connected to a hydraulic group which actuates the device. The device is provided with a keel wing and a counterbalance or lift wing joined by a bulb, a cylindrical actuator for the counterbalance and lift wing, a hydraulic rotary actuator for hoisting the assembly, an articulation shaft, and a tilting shaft for the assembly which is coupled to the broadside or to the mounting base beside sensors of the angle of attack of the counterbalance wing. The hydraulic group and the cylindrical hydraulic actuator are optionally replaced by a cylindrical electric actuator connected to the control panel and acting upon the counterbalance wing.