Sea going trailing suction hopper dredge forms long straight dredging tracks with narrow width, and the dredging configuration is mostly rough. Further the dredging efficiency at final dredging stage which requires high accuracy on dredging depth is always unsatisfactory.
　On the improvement for the inefficient aspects, the use of leveling blades attached to both side of a conventional draghead would be one of effecitve methods to minimize the unevenness of dredged area during earlier dredging stage.