The invention relates to a retractable device which can reduce the shake of a ship and can generate thrust force. The retractable device is used for a ship to reduce swing and leads the ship to advance or retreat. The retractable device comprises two rotary floating plates which are symmetrically arranged on both sides of a hull, the rotary floating plates are used as airfoils of an airplane, thesections of the airfoils are in streamline shapes and are sheathed on a fixing shaft which is connected with a hydraulic cylinder rod, a torsion spring is connected with the fixing shaft, the other end of the spring is connected with a rotating wing plate which is connected with a top rod, and the top rod is connected with the rotating wing plate by a gimbal joint and is driven by an air cylinderpiston. The invention can automatically regulate the swing of the hull to smooth the hull; the retractable device can be folded by the top rod when not used; when the ship loses power, the device canuse waves to generate the thrust force to lead the ship to advance; when the ship needs to retreat, and the place between the fixing shaft and the rotating wing plate is processed, the rotating wing plate rotates an angle, thereby generating reversed thrust force.