Offshore contractor Allseas has signed a construction contract with Guangzhou Shipyard International (GSI) in China for a purpose-built semi-submersible heavy transport vessel (HTV), marking a major expansion of its fleet capabilities.
The vessel, to be named Grand Tour, is scheduled for delivery in the first quarter of 2028. With a load capacity of 40,000 tonnes, the ship will be designed to carry the world’s largest offshore structures across oceans and transfer them to Allseas’ flagship vessel, Pioneering Spirit, for installation.
Grand Tour has been engineered to fit precisely inside the bow slot of Pioneering Spirit, enabling a seamless link between transport and installation. Allseas said the integration would provide clients with a ‘one-stop-shop’ solution for transporting large structures fabricated far from their installation sites.
Supporting Europe’s energy transition, Grand Tour will play a key role in Allseas’ execution of TenneT’s landmark 2GW offshore wind program, which will deliver 28 gigawatts of clean offshore wind power to European homes and businesses by 2032.
The vessel will transport very large converter stations from fabrication yards in Asia and Europe to installation sites in the Dutch and German North Sea, where Pioneering Spirit will take over for single-lift installation.
The vessel features a semi-submersible hull with a 57-meter beam for enhanced stability and shallow-draft access, and an advanced ballast system capable of pumping 24,000 cubic meters per hour – equivalent to 10 Olympic swimming pools – for safe, precise load transfers.
A methanol-ready 24 MW propulsion system, with the option to transition to e-Methanol, will secure competitiveness in a changing energy market, while an air lubrication system under the hull and podded propulsion will reduce drag and fuel consumption.
Its 180 by 57-metre cargo deck is designed for direct skidding, roll-on/roll-off and float-on/float-off operations.
“This addition to our fleet is more than an expansion – it’s a strategic investment that enhances our ability to deliver fully integrated Transport & Installation (T&I) solutions for some of the world’s most ambitious offshore energy projects.
“By keeping transport and installation in-house, Allseas can reduce risk, streamline schedules, and offer clients unmatched reliability in delivering complex offshore infrastructure,” said Pieter Kambier, Project Director.
Beyond offshore wind, Grand Tour will also enable Allseas to relocate its own fleet assets and enter new floating cargo markets, opening long-term opportunities across multiple sectors.