Rotech Subsea delivers key inter array cable burial at Dutch deepwater offshore wind farm

In Q1, 2022, Rotech Subsea was active in European waters again, facilitating a key inter array cable repair at an offshore wind farm on the Dutch Continental Shelf. The Controlled Flow Excavation (CFE) pioneer was contracted by a tier one marine contractor for the IRM scope. Rotech’s powerful TRS1 CFE tool - from its sector-leading RS range of trenching and excavation equipment - was mobilised to carry out 440m of remedial burial and 140m of post-lay burial to client specification of 1.5m depth.

Deployed by crane from an offshore support vessel, the TRS1 was suspended above the cable, traveling along the cable route at a rate of 4m/min in water depths of 20-30m - some of the deepest found at any OWF around the globe.

The cable burial was carried out in soft silty and soft clay soils  with the TRS1’s outlet pressure of 80kPa and maximum jet flow of 3,400L/s completing the job in just two passes. Currents experienced ranged from 0.6-1.4kts with sea state of 1m Hs.

“The Rotech Subsea team and the support vessel deck crew from this valued client worked really well together again to ensure an efficient tool launch and successful project overall,” said Rotech Subsea Director of Subsea, Stephen Cochrane. “Our TRS1 CFE tool excelled, achieving the required cable depth of 1.5m with ease with trench depth monitored in real time using a tool-mounted sonar imager.”

The Aberdeen-based contractor’s in-house research, development and engineering team has created a suite of 18 state-of-the-art, non-contact CFE, Suspended Jet Trenching tools. With enhanced capabilities, Rotech Subsea’s CFE suite of tools is firmly established as the method of choice for offshore wind farm cable trenching and excavation in Europe and beyond.

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