Rotech Subsea completes North Sea cable recovery works

4C Offshore | Tom Russell
By: 13/09/2022 Rotech Subsea

Rotech Subsea has completed key cable de-burial, cut and recovery works at a North Sea offshore wind farm for a dredging and marine contractor.

Aberdeen-based Rotech Subsea deployed its RS2-3 Hybrid CFE tool to complete the de-burial of approximately 500m of cable, with its proprietary RSG-C tool completing the cable cutting at both ends and recovery to ship’s deck.

Operating in water depths of 12-15m, Rotech’s RS2-3 was launched into the North Sea by vessel crane where it was suspended, traveling along the half a kilometre of cable to complete de-burial operations. With a total excavation depth of 2m required, the depth was monitored in real time using a tool-mounted sonar imager, with the de-burial completed in two passes.

Rotech Subsea Director of Subsea, Stephen Cochrane, commented: “With hard soils expected, this promised to be a challenging project. In preparation we deployed an extra RS2 excavator to have on standby to give the option of using the tools in twin ‘TRS2’ configuration to give maximum flow.

“Despite hard, sticky clay experienced, the works were carried out in just two passes, one with the RS2-3 hybrid solution, which boasts a maximum outlet pressure of 300kPa and a max jet flow of 4000L/s, and one pass with the TRS2 configuration capable of 8000L/s of flow.”

Launched from the vessel stern, Rotech’s bespoke RSG-C spread of equipment grabbed, cut and recovered the de-buried cable to deck successfully.

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