A cutter suction dredger combines mechanical and hydraulic dredging methods. To ensure the quality of underwater digging depth (i.e., the flatness of the seabed after excavation and the depth of the dredged material), it is necessary to use steel piles and their hoisting devices or a three-line positioning system installed on the hull for positioning and moving the vessel forward and backward. The side-to-side swing of the hull is achieved by the two side swing anchors connected to the dredging winch bridge.