Abstract: The present invention relates to a vessel comprising an excavator for dredging or shifting soil for cleaning watercourses, the excavator comprising; a weight balanced boom hingeably supported around a boom hinge axis, a bucket-arm hingeably connected to the boom, and provided with a bucket and/or digging tool at a free end of the bucket-arm, wherein a counterweight is connected to the boom and wherein the counterweight is positioned with respect to the boom such that a centre of gravity of the counterweight is above and about vertically aligned with the boom hinge axis when the bucket and/or digging tool is at a lowest digging position.

Abstract: A vessel (1) for forming a trench in a water bottom (100) includes a ladder (2) and trenching elements mounted to the ladder (2). The trenching elements are formed by a first upwardly inclined auger (10) for forming a first inclined trench wall (101) and a second upwardly inclined auger (20, 20?) for forming a second inclined trench wall (102). The first auger (10) is arranged to be rotated to move material of the water bottom (100) in an upward direction along the first auger (10).