Jan De Nul expands subsea cable capability with shallow-water trencher

Jan De Nul is expanding its subsea cable installation fleet with a new remotely operated trencher designed specifically for cable burial in shallow water.

Named Crayfish, the subsea robot is due to join Jan De Nul’s trenching fleet by the end of 2026. It will be permanently deployed from Henry Darcy, a shallow-draft vessel currently being converted from a water injection dredger into a dedicated trenching support vessel.

Built by UK engineering specialist Osbit, Crayfish will be capable of burying cables to depths of up to 5m in water depths of up to 200m. Its lightweight and modular construction is intended to reduce its impact on the seabed while allowing the unit to be transported and mobilised between projects.

The system has been configured specifically to overcome one of the limitations of conventional trenching technology in shallow water. Rather than carrying its high-pressure jet pumps on the trencher itself, Crayfish will receive pressurised water from pumps installed aboard Henry Darcy.

The pumps are being repurposed from the vessel’s previous role as a water injection dredger. High-pressure water will be transferred through a hose to Crayfish, loosening the seabed ahead of the trencher as it advances along the cable route.

Jan De Nul said locating the pumps on the support vessel allows Crayfish to operate closer to shore, where water depths can prevent conventional trencher-mounted jet pumps from operating effectively.

The unit’s first deployment is scheduled for summer 2027 in the German North Sea, where it will support Jan De Nul’s 2 GW cable programme for German transmission system operator TenneT. The project forms part of the company’s broader expansion of its subsea cable installation and protection capabilities.

Jan De Nul fleet

Jan De Nul has invested heavily in its offshore energy fleet over the past several years. Its existing cable-laying fleet includes Isaac Newton, Connector and Willem de Vlamingh, while two 28,000-tonne cable-laying vessels, Fleeming Jenkin and William Thomson, are being added in 2026. The 215m vessels are designed to install cables in both shallow and ultra-deep water, including at depths of up to 4,000m.

The company is also adding dedicated vessels for cable protection and burial. Jan De Nul says four vessels are being added to its subsea energy cable fleet, with one existing vessel undergoing conversion.

The expansion reflects the growing importance of subsea cables to offshore wind development and cross-border electricity interconnection. Jan De Nul’s new cable-laying vessels, for example, are being deployed on TenneT’s programmes to connect offshore renewable generation to the electricity grid.

With Crayfish and Henry Darcy, Jan De Nul is adding a more specialised shallow-water capability to that fleet, extending its ability to install and protect subsea cables through the transition from deeper offshore waters towards the nearshore environment.