Cutter suction dredging
The cutter suction dredger (CSD) is the most common type of dredger. The CSD has two main components; the cutterhead and the dredge pump. A rock cutter suction dredger excavates with a cutterhead of typically 3 m diameter armed with a number of pick points. The mechanical description of the operation of a cutter suction dredge is extremely complicated. The rotation of the cutterhead can produce a sediment cloud, not only when dredging in fine sands, silts or clays, but also when cutting rock types like weak limestones. The cutting teeth or pick points on the cutterhead take up different radial positions on the cutting blades and therefore each have different cutting velocities. An important aspect of cutting tool design is that friction between soil-rock and the tool is to be prevented or minimized. A commonly used quantity to describe efficiency is the specific energy, which can be estimated on board of the dredger.