Mechanical Dredging

Grab Dredger/Clamshell Dredger

Area of Application:
The large grab dredgers are used for bulk dredging. While the smaller ones are mostly used for special jobs, such as:

  • Difficult accessible places in harbors.
  • Small quantities with strongly varying depth.
  • Along quay walls littered by rubbish and debris.

The production of a grab depends strongly on the soil. Suitable materials are soft clay, sand and gravel. In soft soils light big grabs are used while in more cohesive soils heavy small grabs are favorable. The dredging depth depends only on the length of the wire on the winches. However the accuracy decreases with depth.