Abstract: For dredging cohesive soils (and even non cohesive soils) cutter heads are frequency used to des-integrate the soil. During the latest fifty years, cutter heads have been improved greatly. There are good reasons for the current shape of cutter heads. Therefore the authors were surprised by the article “The Secret of Dredging Rock” in Dredging and Port Construction of September 2004. The author of that article pleaded for a cylindrical cutter head when dredging rock for the reason of a higher inertia compared to the “conventional” cutter head. A cylindrical cutter certainly has a

higher inertia compared to a basket cutter with the same cutter ring diameter, but a cylindrical cutter head has much more disadvantages than the advantage of a higher inertia. 

In this paper the theoretical background of the cutter head contour, the helix of the cutter head blades and the positioning of the teeth on the blades in relation with its cutting and its mixture forming process, will be discussed.