IWS CSOV named 2025 offshore energy vessel of the year

The 2025 Offshore Energy Vessel of the Year Award went to 90-m CSOV IWS Seawalker during a ceremony at the Annual Offshore Support Journal Conference in London in February 2025.

Designed by Kongsberg Maritime and built by China Merchants Industry Holdings for Norway-based shipowner Integrated Wind Solutions, the vessel was built with several superlatives in place, including the largest battery packs in the industry with solar panels for additional charging.

“We greatly appreciate the good co-operation with IWS. That we have received this award together is just amazing,” Kongsberg Ship Design vice president Ronny Pål Kvalsvik said. “This series of vessels is a game changer in the offshore wind space.”

Integrated Wind Solutions latest windfarm commissioning, service and operation vessel IWS Seawalker was built to Kongsberg’s UT5519 DE design as part of the Skywalker series. It was named in a ceremony in the port of Hanstholm, Denmark at the end of October 2024 and was the third of an expected six Skywalker-class vessels to be delivered.

The vessel has several industry firsts, according to Kongsberg. For one, the ship sports a novel hull and propulsion design that increases operability and reduces emissions. The UT 5519 DE ship design’s double-ended hull form and propulsion set up draws on Kongsberg Maritime’s inhouse research and development and operational experience in windfarm service vessel design that minimises emissions and maximises manoeuvrability and efficiency. 

"The double-ended configuration is perfect for DP and the walk-to-work application. Kongsberg Maritime’s DP system allows the operator to use a fully automated mode when travelling between turbines on a predefined transit plan for maximum efficiency," Kongsberg said.

IWS Seawalker is equipped with the latest-generation 3D compensated gangway and crane systems, the largest battery packs in the industry with solar panels for additional charging, and the vessels are the first in the industry to have the DNV Silent notation, which focuses on minimising impacts from acoustics and vibration on marine life. The Skywalker-class vessels have IMO Tier 3 engines and a 2.2-MWh battery pack, with main propulsion coming from four US 255 L PM azimuth thrusters, with permanent magnet motors. The setup creates a symmetrical propulsion and manoeuvring system, matching the symmetrical hull design, fore and aft.

The Skywalker class was designed specifically for offshore wind operations, focusing on reduced emissions and enhanced sustainability. Kongsberg Maritime had an extensive scope of supply for all six Skywalker-class ships. 

“This design is a result of how we like to do naval architecture,” said Kongsberg Maritime vice president of ship design solutions, Einar Vegsund. “It has a double-acting hull; onboard energy storage provides a power boost and enables normal operations using just one generator and the batteries. There are two azimuth thrusters on both ends, low noise and minimal roll of the vessel for comfort for crew and technicians.”