A dredger ship, dredgers also, is a hydraulic vehicle that has special equipment for dredging of harbors, estuaries, bays or the like. Commonly used as often in the field of shipping, the English expression Dredger.
A distinction is made between the Herstellungsbaggerung such as the deepening of the Elbe and the continuous need for maintenance dredging. This dredging is repeatedly necessary in mouths of many rivers, as these waters settle sediments that become shoals, which may affect the shipping industry.
Also, for the recovery of raw materials mass, such as sand and gravel plants, dredgers are used when the drying up of the mining area is not possible ( Stretch ). Similarly done the extraction of minerals (metals / ores, minerals, gemstones, ...) from placer deposits, such as gold- diggers.
Another possible application is the extraction of sand from the seabed for the purpose of hydraulic filling, that is, in the context of land reclamation for airports or construction areas or for application of ports.
Operation and dredging method
Differences are in the dredging bucket dredgers and suction dredger, and anchored for smaller jobs on ships or barges or pontoons unpowered cable or hydraulic excavator with grab bucket. The suction dredgers have the bucket chain excavators because of the high efficiency, simpler technology and better working results largely displaced. Bucket chain excavators are now used only in special situations such as to release a very firm soil types such as marl. The cutter suction dredgers Excavators and hopper dredger can be distinguished. Modern dredgers are equipped with powerful suction and pumping equipment, such as the Vasco da Gama. You can further promote the dredged material in different ways and usually have their own cargo spaces or be accompanied by freighters ( barges ) conveying the dredged material to the destination.
If the dredged material is heavily polluted by human activity such as industry, agriculture and sewage systems, it can not be dumped in open waters, but is purified, for example in Hamburg or in specially built disposal basins (for example, off the Dutch coast from Rotterdam) or country landfilled. In particular, for coastal Saugbaggereinsätze wash trays are set up on land to which the extracted sand -water suspension is flushed through pipelines. Also in dike construction in sand core levees or Aufhöhung of port operation areas the dredged material has often been used.
Are used dredgers, among other Royal Boskalis Westminster by the company, which operates about 300 dredgers world and its main competitors, the Belgian Dredging International NV and the Dutch company Van Oord and Volker Stevin Marine Contracting ( VSMC ) and the Luxembourg Jan de Nul Group are to be counted ( with Dutch roots).