Dredging is the digging or pulling out of material in the sea or ocean in order to deepen waterways, make harbours, berths, docks, desilt lakes & clear river entry e.t.c.
Dredging can be classified into two :-
- Mechanical dredging
- Hydraulic dredging
TYPES OF DREDGERS
- Trailer Suction Hopper Dredgers -itis a hydraulic dredging vessel that lowers a drag head into the sea bed and moves the sediment and water mixture through the drag arms into hopper bins. They discharge by pipeline or barge.
- cutter suction dredger – this are also known as CSD. They have a rotary cutter head that helps loosen the earth and takes its broken pieces to the suction mouth. this hydraulic dredging vessels discharge through a pipeline or barge.
- Bucket ladder dredgers – this are mechanical dredging vessels that use a series of buckets that are mounted on a conveyor ladder. that sends debris upwards from the sea bed. they are very efficient in the ripping of coral as well. they discharge by pipeline or barge.
- back hoe dredger – it is also known as dipper dredger. this resemble a true backhoe plant equipment. they are mechanical dredgers that have a bucket that scoops out sand from the water bed. This is a mechanical dredger vessel that that discharges by barge.
- grab dredgers – This are mechanical dredger vesels with a vice hand like equipment for grabbing sand from the water bed which is held or suspended from a crane. it discharges on a barge.
- water injection dredger – it is a hydraulic dredger vessel that works by fluidizing the ground surface by pumping water into the bed material. it is then later either moved by a second burst of water or is carried away by natural current. it discharges as it operates.