The primary advantage of a CSD is that it is able to dredge hard materials that most trailing suction hopper dredgers cannot handle. In addition, self-propelled CSDs are almost as flexible as a trailing suction hopper dredger, because they too can use their propulsion systems during mobilisation to a dredging site. This makes them cost-effective. In addition, they can be moved from one place to the other in the channels or when the dredging area has to be left, for instance, when inclement weather is expected.
Although stationary CSDs cannot do this, small to medium sized stationary CSDs can often be supplied in a demountable form. This makes them suitable for transport by road to inland sites that are not accessible by water, for example, to lay a sand foundation for a road or to dredge sand and gravel for the building industry.
WHAT SAFETY FACTORS SHOULD BE CONSIDERED?
Nowadays safety and sustainability are considered part and parcel of every seagoing vessel and CSDs are no exception. The newest CSDs take advantage of the high-tech possibilities to insure technical and constructional features that comply with the highest standards. For instance, because of the type of work they do – breaking hard rock and soils – CSDs are known for their high sound and vibration levels. The intensity of sounds varies depending on the amount or hardness of the material to be removed. To ensure that the crews have comfortable working environment and living quarters, new ships have better insulated living areas.
WHEN IS A CSD THE APPROPRIATE CHOICE FOR DREDGING?
CSDs are largely used in the dredging of harbours and fairways as well as for land reclamation projects when harder material needs to be dredged. They are also used when the distance between the dredging and disposal areas is shorter than the distances covered by trailing suction hopper dredgers. CSDs also have the advantage when an accurate profile has to be dredged. CSDs can dredge almost all types of soil if the installed cutting power of the cutter head is appropriate. Because of the availability and versatility of a wide range of large and small cutter suction dredgers, the most diverse projects can be tackled.