Allseas orders unique heavy transport vessel for offshore wind

Named Grand Tour, the vessel is being purpose-built to fit inside the bow slot of Pioneering Spirit, allowing the two vessels to work together as an integrated transport and installation system.

Once alongside, Grand Tour will ballast down so that its cargo can be floated directly onto its deck before the vessel brings the load into position for installation.

Named Grand Tour, the vessel is due for delivery from Guangzhou Shipyard International in 2028 and will transport converter stations from fabrication yards in Asia and Europe, filling a gap in the logistics chain for Europe’s offshore wind industry.

Grand Tour has a 57m beam and will carry loads of up to 40,000 tonnes on its stern deck. The vessel will carry loads of up to 40,000 tonnes on its stern deck and must accurately position itself alongside Pioneering Spirit before ballasting down to allow converter stations to float directly onto its deck.

Power & propulsion

ABB is supplying four 3.5MW nozzled Azipod propulsion units, providing the thrust, 360-degree rotatability and precise manoeuvrability required for heavy transport and dynamic positioning operations.

The gearless Azipods are designed to minimise mechanical losses, fuel consumption, noise and vibration, while their compact footprint gives greater flexibility in the vessel’s design, ABB says. The absence of gearing also reduces lubrication requirements and maintenance.

ABB is also supplying the vessel’s medium-voltage AC power plant in a closed-ring configuration, controlled by its Power and Energy Management System (PEMS), together with an enhanced power plant protection system and remote condition-monitoring and maintenance capabilities.

The four Azipods will be complemented by a 2.6MW retractable azimuth thruster and two 2MW tunnel thrusters, giving Grand Tour DP2 capability and additional control when manoeuvring around Pioneering Spirit.

“It’s fantastic to see our power and propulsion technology delivering such strong value in demanding heavy‑lift operations,” said Rune Braastad, President, ABB’s Marine & Ports division. “Projects like this demonstrate how advanced, integrated systems can make operations leaner, cleaner and more efficient, raising performance and safety to a new level, while also opening new market opportunities.”

Power will come from four 6MW diesel generator sets, with the vessel designed for future methanol operation. The design also incorporates an air-lubrication system intended to reduce hull resistance and fuel consumption during transit.

Ballast and alternative fuels

Ballast capacity is another key part of the vessel’s technology. Eight ballast pumps provide a combined capacity of 24,000m³/h, with total ballast capacity of 165,000m³. This will allow the vessel to make the controlled changes in draft required during heavy-cargo operations.

Vuyk Engineering, which developed the concept and basic design, says Grand Tour combines its experience in semi-submersible transport vessels with its work on alternative fuels.

“Grand Tour builds on our expertise in semi-submersible transport vessels and alternative fuels, and reflects our shared commitment to innovation, efficiency, and sustainability in offshore transport and installation,” said Vuyk Engineering director Floris Toetenel.

The vessel is unusual not simply because of its size, but because its systems have been developed around a specific transfer operation.

Its propulsion, DP and ballast capabilities will allow it to act as a precisely controlled transport platform before handing its cargo directly to one of the world’s largest construction vessels.

The video shows Allseas’ installation vessel Pioneering Spirit at work in the field.