A cutter suction dredger is a combination of mechanical and hydraulic dredging vessels. To ensure the quality of underwater dredging depth (i.e., the flatness of the underwater seabed after dredging and the depth of the mud removed), it is necessary to use steel piles and their lifting devices or a three-line positioning device mounted on the hull for positioning and the ship's forward and backward movement. The side-to-side swing of the hull is achieved by the two side swing anchors connected to the bridge of the dredging cutter.