North Sea wind buildout spurs Allseas to order giant transport vessel from China

Allseas and Hereema are top installation companies for oil and gas, but both see offshore wind as growth vehicle

A computer generated image of the transport vessel that will transport grid and wind farm infrastructure to the North Sea
A computer generated image of the transport vessel that will transport grid and wind farm infrastructure to the North SeaPhoto: Allseas

Allseas, an offshore contractor led by Dutch industrialist Edward Heerema, has ordered a giant heavy transport vessel (HTV) from a Chinese shipyard in response to the growing scale of grid and wind farm infrastructure under construction in the North Sea.

A semi-submersible HTV with a 40,000 load capacity will be built by Guangzhou Shipyard International (GSI) to carry large converter stations from originating yards in Asia and Europe to installation sites in the Dutch and German North Sea, Allseas announced.

Anchor projects for this newbuild order include slice of the massive offshore infrastructure expansion under way by Dutch transmission system operator TenneT.

Allseas was one of two contractors selected by TenneT earlier this year to deliver at least 14 offshore platforms under a 2GW grid expansion programme.

This forms part of a much bigger Dutch plan to add 28GW of incremental renewable energy capacity by 2032.

The new HTV, which will be named Grand Tour, is designed to work in synergy with Allseas’ own Pioneering Spirit single-lift installation vessel. The new vessel is designed to fit exactly inside the bow slot of the latter.
“(The Grand Tour) is designed to carry the world’s largest offshore structures across oceans and easily transfer them to the Pioneering Spirit for installation," the company stated.

“This integration will streamline the offshore installation process, and offer... a one-stop shop for transport and installation of large structures fabricated far away from the installation location.”

The new vessel will also feature a methanol-ready 24MW propulsion system to respond to future requirements on shipping emissions in the North Sea.

Delivery of the vessel is scheduled for the first quarter of 2028.

Heavy transport vessels

Chinese shipyards have been churning out a growing number of HTV vessels for offshore wind markets in recent years, but data compiled by Clarksons Securities show that the vast majority are for China's domestic market.

One exception is the Seaway Alfa Lift large heavy lift crane vessel with 40,000 tonnes of cargo capacity, which was built for Seaway 7 by China’s CMHI shipyard in 2023.

This vessel, which can carry up to 40,000 tonnes of cargo and equipment, is currently working on the giant Dogger Bank C wind farm development in the UK North Sea.

Brothers at sea

Allseas will be working on the TenneT projects alongside heavy-lift specialist Heerema Marine Contractor (HMC), which is controlled by members of the same family.

In the early 1970s, when the North Sea oil and gas arena was in its infancy, it was Heerema that came up with the idea of placing big cranes on large semi-submersible vessels.

HMC stepped up its own efforts to expand into the offshore wind market in 2018, when the company decided to exit the pipelay market.
One of HMC's giant semi-submersible crane vessel, the Sleipnir, is already working on the TenneT grid expansion projects. The company recently built a new flat-deck barge to facilitate float-over installation methods.
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Published 11 September 2025, 14:09Updated 12 September 2025, 08:10
AllseasNetherlandsHeerema