Launching ceremony held for Jan De Nul’s second cable-lay vessel

The vessels have a cable-carrying capacity of 28,000 tonnes and a length of 215 m, making them the largest of their kind.

Like sister vessel Fleeming Jenkin, William Thomson was launched at the CMHI Haimen shipyard in China.

Fleeming Jenkin was launched in October 2025 and is due to be delivered in Q4 2026. William Thomson will be delivered shortly after that and will be operational in the first half of 2027. Both vessels were designed by Jan De Nul inhouse and are capable of laying cables at a depth of up to 4,000 m.

Once operational, Fleeming Jenkin and William Thomson will immediately start their first assignments, working on Tennet’s 2GW programme. Fleeming Jenkin and William Thomson will install more than 2,800 km of 525-kV HVDC cables for four different grid connections.

In 2028, Jan De Nul will also deploy one of the new cable-laying vessels to install three 220-kV AC cables that will connect the Princess Elisabeth energy island to shore. 

The energy island, which Jan De Nul is building in a joint venture for grid operator Elia, will bundle the cables from Belgium’s second offshore wind zone, the Princess Elisabeth Zone, and enhance the interconnection between the North Sea countries.

Jan De Nul is investing heavily in expanding its existing cable capacity and, in addition to Fleeming Jenkin and William Thomson, has three more vessels on order, including two trenching support vessels to bury cables in the seabed and a rock installation vessel to install rock to protect them.