Abstract: In the past decade there were some striking trends in small trailing suction hopper dredger design. On the one hand there was an increase in scale, but on the other hand the working area especially the water depth in which the dredgers have to operate became shallower.

Coastal defense in the Netherlands is an example of this. In the past the sandy coast was protected by pumping sand on the beaches. Nowadays another method has been introduced. This method implies that the sand is not only pumped ashore, but is mainly dumped along the coastline. This under water replenishment has led to a dredger design with special features.

Although the coastal defense dredger can be seen as a specialized dredger, this type of dredger must also compete in other markets. This is a problem each dredging company meets. Specialization gives a more cost effective dredger for a specialized market but when other dredging jobs have to be carried out, specialization can be a handicap.

These and other trends will be discussed.

This paper will address a number of parameters in the design of a trailing suction hopper dredger. Cost per volume dredged (cubic metre) will be the vehicle used to evaluate the economic factors influencing efficiency from an economic point of view.