A new design of offshore wind crew transfer vessel being constructed in the UK will combine cutting edge hybrid and air cushion technologies for the first time.

Wight Shipyard Co, an aluminium shipbuilding specialist on the Isle of Wight has been contracted to build the world’s first hybrid surface effect crew transfer vessel, which will service the Borssele 1 and 2 offshore windfarms located 23 kilometres off the Dutch coast.

“We have built a reputation in the fast ferry arena and commercial marine sector,” said Peter Morton, CEO WSC. “But this a world first, building a hybrid SES for crew transfer. Building greener vessels has been an integral focus for some time now so we are well placed to lead this step change in Crew Transfer Vessels.”

WAVE HANDLING
WSC will manage the build project from its development stage right through to delivery. The vessel will be a game-changer for the industry because of its ability to handle 2m significant wave height during technician transfer in heavy seas. At the same time, it will decrease fuel consumption and CO2 emissions.

The Hybrid SES propulsion engine will deliver sprint speed and extreme bollard push from its 1,600kW installed diesel engines, which can be battery boosted up to 1,500kW. Significant fuel savings will be achieved through balancing engine and inefficient low engine power running hours, with battery drive modes including windfarm standby and low speed/harbour operations. This will lead to an engine operating hour reduction of 50% during windfarm battery standby.

Martyn Drye, Director of Engineering at CWind said, “We embarked on the design of this revolutionary project last year, which utilises new technology to meet industry drivers for improved performance and reductions in carbon emissions. We’re proud to be delivering a concept which is at the forefront of CTV innovation and look forward to a collaborative working partnership with Wight Shipyard Co over the coming months for the build of this vessel. WSC have been great to work with during the pre-contract stage and have embraced the new technology for this vessel. We are confident that they will deliver a high quality solution, on time.”

SES TECHNOLOGY
The Hybrid SES crew transfer vessel was developed in partnership with the operator CWind and ESNA, a ship design company based in Kristiansand, Norway, which specialises in commercially competitive vessels with surface effect technology to deliver significant carbon reductions.

Consisting of two catamaran hulls with the area between the hulls closed, by flexible reinforced rubber fingers in the bow and an inflated rubber bag in the stern. Centrifugal fans blow air into this enclosed space, providing an air cushion that supports up to 80% of the vessel weight. The remaining 20% is supported by hull buoyancy. This allows for higher vessel speed because the hull resistance is significantly decreased. It also reduces motion owing to less wave contact. In addition, the air cushion acts as a large shock absorber, improving the seakeeping and reducing seasickness.

CWind’s long-term charter contract agreement with Ørsted, which operates the Borssele 1 and 2 offshore windfarms, will start in mid-2020. The agreement will cover an initial three-year firm charter with options available for a further two years.