Jan De Nul launches second giant cable-laying vessel William Thomson for offshore wind and grid interconnection projects

Belgian marine contractor Jan De Nul launched its second next-generation cable-laying vessel (CLV), William Thomson, in April 2026, designed to support growing offshore wind and grid interconnection projects. The vessel, measuring 215 meters in length with a cable-carrying capacity of 28,000 tonnes, can install longer subsea cables in a single campaign and operate in water depths of up to 4,000 meters. Equipped with three cable carousels and capable of laying up to four cables simultaneously, the William Thomson will join its sister ship Fleeming Jenkin—launched in October 2025—in deploying on Jan De Nul’s first assignment under the 2GW offshore grid program led by TenneT in the Netherlands and Germany. The program involves installing over 2,800 kilometers of 525 kV direct current subsea cables across four grid connections, each capable of transmitting up to 2 GW of power. One of the vessels will also support future projects, including cable installation for Belgium’s Princess Elisabeth Island energy hub, which connects offshore wind farms and strengthens interconnections between North Sea countries. The new vessels incorporate hybrid power systems with a 2.5 MWh battery and engines capable of running on biofuel and green methanol, alongside emission-reduction technology to meet strict European standards.

Counterparts (3)

supplier

C

CMHI Haimen shipyard

company

Offtaker

T

TenneT

company

Dutch national transmission system operator managing high-voltage electricity grids in the Netherlands and Germany. Operates over 25,000 MW of transmission capacity across Western Europe, with major investments in offshore wind integration and cross-border interconnectors.

Developer

Jan De Nul

company

Jan De Nul Group is a leading Belgian family-owned infrastructure contractor specializing in dredging, marine construction, civil engineering, and offshore energy infrastructure. With over 7,000 employees, it operates globally, delivering complex projects from port development and land reclamation to offshore wind farm installation and subsea cable laying.