Dedication to offshore wind



Offshore wind energy generation is one means to reach international climate goals. ULSTEIN has been developing offshore wind designs since 2006. The designs draw on our broad experience in oil and gas, and range from new turbine installation concepts to foundation installation vessels and service operation vessels.

Film above: The 'Siem Moxie' at work. The active motion compensated gangway is transferring people directly onto the turbine's TP platform and the 3D motion compensated crane is lifting the Offshore Support Unit over to the turbine. The vessel was later acquired by Subsea7 and renamed 'Seaway Moxie'.

Ulstein's offshore wind history

Ulstein’s entry into the offshore wind market started with a new installation concept for wind turbines, the F2F (Floating to Fixed) concept back in 2006. This was followed by our first designs for Service Operations Vessels (SOVs)/Installation Support Vessels (ISVs) and foundation installation vessels (FIVs).

Our designs and solutions now cover all stages in the development of an offshore wind farm: Planning & development, Substructure installation, Installation & Commissioning, Operations & Maintenance, and Decommissioning & Repowering.

Zero emission turbine installations now available

Introduced in October 2020, Ulstein's second hydrogen hybrid design for the offshore wind industry, the ULSTEIN J102 zero emission wind turbine installation vessel (WTIV), can operate 75% of the time in zero emission mode. Using readily available technology, the additional cost is limited to less than 5% of the total CAPEX.

Planning & development

This stage needs survey and IMR (Subsea/Inspection Maintenance Repair) vessels. These vessel types are closely linked to our offshore portfolio of vessels, of which we have developed numerous projects, see reference list.

Substructure installation

Survey and IMR vessels, cable laying vessels, rock installation, floating installation and handling equipment are all part of this stage in the establishment of an offshore wind farm.

Cable lay
Ulstein has delivered several cable lay vessels, and the most recent 2021 newbuild, the state-of-the-art CLV, 'Nexans Aurora', has been constructed at Ulstein Verft, Norway, for Nexans.

Rock installation

Subsea rock installation (SRI) vessels are widely used in the offshore industry, stabilising and protecting subsea pipelines, cables and other structures at the sea bed. For the offshore wind industry, SRI vessels also lay protective coverings of rock around turbine foundations, to avoid scouring. Ulstein has a proven track record in developing these highly specialised vessels, the most recent reference being the highly innovative DP3 fall-pipe vessel ‘Bravenes’.

In 2020, Ulstein was awarded a contract by Great Lakes Dredge & Dock to design the first U.S. flagged Jones Act compliant, inclined fallpipe vessel for subsea rock installation. The vessel is critical in building the future of the U.S. offshore wind industry, including establishing a U.S. based rock supply chain network.

Monopile installation

The 'Alfa Lift' semi submersible vessel matches the future requirements of the offshore wind industry, allowing her to transport and install up to 10 x 1,500t ultra-large jacket foundations or 11 x 2,000t XXL monopiles plus transition pieces for the largest anticipated Wind Turbine Generators. The Subway Alfa Lift vessel for ship owner OHT is currently under construction at China Merchants Heavy Industry (CMHI) in China.

The 'Alfa Lift' vessel of Ulstein design will be the largest and most innovative, custom-built offshore wind foundation installation vessel in the world. The vessel is due for delivery 2021/22.

'Seaway Moxie' ISV operates as a duo

The ‘Seaway Moxie’, an ULSTEIN SX163 design delivered in 2014, is operated by Seaway Offshore Cables, a Subsea7 company. She often works as part of a duo, in which Seaway Moxie operates as an ISV, together with the cable laying vessel Seaway Aimery. The Seaway Moxie’s key features are a 3D motion-compensated telescopic crane and an active motion compensated personnel transfer gangway, permitting the safe transfer of work crews in significant wave heights up to 3.0 m. Thanks to the ship’s active roll stabilization capabilities, offshore works can continue even in challenging sea and wind conditions.

Installation & Commissioning

Service operation vessels and jack-up installation vessels are vessels for this stage.

Our first two SOV/ISV deliveries were awarded the 'Offshore Renewables Award', in 2014 (Siem Moxie - now: Seaway Moxie) and 2017 (Windea La Cour). Our X-STERN® solution was awarded the Next Generation Ship Award in 2015.

SX175/SX195 designs for BS Offshore
Two SOV vessels of the SX175 design have been developed for BS Offshore (Bernhard Schulte), introducing the novel X-STERN feature. The vessels are servicing offshore wind farms on contract for Siemens. The ‘Windea La Cour’, delivered 2016, received her first contract for the Gemini Offshore Wind Park offshore the Netherlands. The ‘Windea Leibniz’, delivered 2017, was assigned to service the two Vattenfall offshore wind installations, Sandbank and DanTysk offshore Germany. The two vessels have an active motion-compensated ‘Walk to Work’ (W2W) gangway, which is used for the safe transfer of maintenance teams to and from the individual turbine foundations in significant wave heights of up to 2.5 m or more.

Bernhard Schulte later ordered a third SOV vessel, the WINDEA JULES VERNE, of the larger SX195 design, delivered from Ulstein Verft in 2020. This vessel has been contracted to support the maintenance work of GE Renewable Energy at the German wind farm Merkur Offshore.

SX195 for Acta Marine
An SX195 Construction Support Vessel, the Acta Auriga, was contracted by Acta Marine and delivered 2018. The SMST motion compensated gangway has integrated elevator and crane functionality. The vessel can perform 3D compensated lifts with its 6t 3D crane, and has accommodation for 120 people. The vessel was contracted for Operations and Maintenance work at the BARD Offshore 1 offshore wind farm, an assignment completed in 2021. A sister vessel, Acta Centaurus, was delivered from Ulstein Verft 2019. Unlike its sister, this vessel also features a helideck. She has already worked at various European offshore wind parks.

Construction in the U.S. possible
Ulstein holds an Approval in Principle (AIP) for its proven Service Operation Vessel (SOV) design, the ULSTEIN SX195, from ABS - the American Bureau of Shipping.

Ulstein has designed the X-JACK concept for jack-up installations, and lately, a hydrogen version.

Operations & Maintenance

Once more, at this stage vessels for Service Operations, Survey and IMR and cable laying vessels are relevant types of vessels.

Decommissioning & Repowering

Floating installation and jack-up installation vessels are vessels for the decommissioning phase.

Read story:
Hard rocker at work - enjoying the silence

Matthias the hard rocker, senior DP operator on the SOV vessel designed with an X-STERN.
Matthias the hard rocker, senior DP operator on the SOV vessel designed with an X-STERN.