Innovation from
the drawing board

“An exciting contract”, that is what Fokke Jan Botke, ship designer of shipyard Royal Niestern Sander, called the assignment for the Kroonborg vessel. With new techniques that very often one is only allowed to dream about. Service Operation Vessel “KROONBORG”: a new standard combining innovative functions to enable efficient, safe, comfortable and environmentally-friendly offshore support and maintenance.

“Accommodation facilities at sea. Quiet and stable sailing”, according to the functional requirements from our client NAM. Suitable for the transport of maintenance crews, which are not used to sailing. Safety while
underway, but also safe during offshore transfers from a motional vessel to a fixed unmanned platform in the Southern North Sea. Mr. Botke remembers the functional requirements quite well. It gave the opportunity to apply innovative techniques, which are considered too risky by many shipping companies, in the vessel’s design. But Royal Wagenborg and NAM are aware of the added value offered by the combination of these techniques.

A simple drawing made by the client was the basis of the Kroonborg’s design, not only for shipyard Royal Niestern Sander, but also for many sub-contractors, such as Barge Master. This Dutch company developed a new type of motion-compensated crane with a small footprint on the vessel. For the gangway, the shipyard could make use of new but proven technology from another Dutch company: Ampelmann. Her hydraulic system enables the gangway to be stable and horizontal in waves up to 2.5m.

Another important point of departure for the design was the vessel’s stability. A height of 26m would be unexpected, because the higher the vessel, the greater the vessel will break-out. “True, but the vessel also moves more slowly. People usually get seasick due to quick and short rolling motions and accelerations,” according to Mr. Botke. The Kroonborg’s design and propulsion system is focused to repel this type of motion. That is why the vessel is equipped
with two Voith Schneider Propellers, which are excellent for roll damping due to the great speed with which thrust and direction can be adjusted. Moreover, this propulsion system, which includes two extremely low-noise Voith bow thrusters, proves her value during dynamic positioning, in which substantial fuel savings can be made. 

Finally, the choice of GTL fuel, a fuel made of natural gas with less emissions than conventional fuel, results in an absolutely green and clean vessel. “The Kroonborg and her innovative design are probably way beyond their time and will set a new standard in the offshore world. Both the offshore wind and oil & gas industries can benefit from this type of vessel,” concludes Mr. Botke.