Research vessels are difficult to categorize in standard categories. To exaggerate a bit, one could say that they are a cross-over of the hull of a supply vessel and the instrumentation of a navy vessel. They look very com-mon from the outside but are equipped with most sonar or acoustic equipment. It is said that among shipbuilders they have the reputation of vessels that can either save the yard or make them go bankrupt. That has everything to do with the difficulty to calculate the costs for such a vessel as there is in general limited experience building these vessels. These vessels are often one-off's. Besides, it is not always known which measurements have to be taken in the design of the vessel to enable it to have a reliable operational profile. A couple of things play a role here, varying from bubble sweep down at the bow and the design of the structure with regard to inboard noise generated by the engines, up to the noise gener-ated by the propeller.