Kongsberg Maritime has signed a contract with VARD shipyard to supply a large package of permanent magnet (PM) thrusters for installation on two new offshore wind farm maintenance vessels. The Construction Service Operations Vessels (CSOV) are to be built for Rem Offshore, and will make the shipping company the first in the world to install a PM package of this size from KONGSBERG.

The scope of delivery includes PM azimuth thrusters, together with PM tunnel thrusters and a retractable azimuth thruster. PM thrusters contribute to improved manoeuvrability, reduced noise – both in the vessel and in the sea – and higher propulsion efficiency, reducing both energy consumption and environmental emissions. The thrusters will be controlled by KONGSBERG’s K-Master bridge solution, a complete working environment which combines dynamic positioning (DP) and manoeuvring functionality in an integrated, joystick-driven system which can be managed by a single operator.

The package leverages some of KONGSBERG’s most innovative technologies, including solutions to limit vessel movement when close to wind turbines during service assignments and facilitate walk-to-work functionality. The thrusters’ advanced propeller design has been developed at KONGSBERG’s facility in Ulsteinvik, part of a cluster of maritime companies located in the Sunnmøre area in western Norway, and also home to Rem Offshore.

“In the maritime cluster at Sunnmøre, we have a tradition of working together to develop and be first to use new technology that gives us a competitive advantage,” says Åge Remøy, Chairman of the Board, Rem Offshore. “With this project, we are doing it again. Together with VARD and Kongsberg Maritime, we are building a sustainable platform for offshore wind service.”

PM thrusters differ from conventional thrusters in that the propeller blades are not driven directly with a motor and shaft. Instead, an electromagnetic field generates rotation around the outer edge of the propeller blades. This rotational force (torque) is produced by a compact and efficient PM motor integrated around the outer diameter of the propeller.

The system permits direct drive to the propeller, with no gears required, yielding a fast response time with the least possible energy use. This rapid power delivery helps KONGSBERG’s control systems to reduce vessel movements in the sea. PM thrusters are also quiet compared with traditional thrusters, do not require an external cooling system, and take up less space – a consideration of great benefit to ship designers.

“This type of technology is key to the green shift for shipping,” says Ottar Ristesund, SVP Sales, Kongsberg Maritime. “A ship is a complex system of technologies, and our job is to offer integrated equipment that makes the ship a good long-term investment for shipping companies, regardless of the type of fuel to be used. PM technology offers flexibility for the future for vessel owners.”

The vessels will be designed and built by VARD Group, with the first scheduled to be delivered in the first half of 2023. The yard has an option to build two more vessels of the same design.