Propulsion manufacturer Voith Turbo will deliver two electronically controlled Voith Schneider Propellers[ds_preview] (VSPs) of the size 28R5 ECS/234-2 to the infield support vessel (ISV) »Siem Moxie«. The Ulstein-design with x-bow is currently under construction at Norwegian Fjellstrand shipyard and is planned to put into operation in spring 2014. Designed for specific tasks in wind farms in the North Sea as well as in the Atlantic Ocean, the work boat with a length of 74 m, a beam of 17 m and a speed of 14.5 kn will be the first x-bow vessel equipped with VSPs. They have a propulsion power of 1,850 kW each and will be arranged in the stern. They will also be used for active roll stabilization as well as for dynamic positioning (DP class 2). The entire propulsion system as well as the DP system are controlled centrally. The interfaces for propeller and roll stabilization control will be provided by Voith, too.
In addition to wind farm tasks, the Norwegian owner Siem Offshore intends to use the vessel for cable laying operations in the North Sea and in the Atlantic.
Vessels with x-bow are characterized by the absence of a bulbous bow. Their bow slopes backwards above the water line which results in reduced resistance and improved wave slamming characteristics on the foreship. The favourable interactions between the VSP and the x-bow design result in lower vibrations, a reduction in fuel consumption and therefore in reduced emissions. Given the more stable position of the vessel, even adverse sea and wind conditions still permit work to be carried out on the 200 m2 work deck as well as close to the offshore units.
