Rotech Subsea has successfully carried out the cable cut and recovery operation at an offshore wind farm in Denmark.
The Aberdeen-based company was tasked with cutting and recovering a 165 mm-diameter subsea cable in two locations at water depths ranging from 16 to 25 meters, using its proprietary RSG/C grab and cut tool.
Deployed by vessel crane, the RSG-C tool was controlled using a single deck winch routed through a fairlead at the aft of the vessel.
Rotech Subsea explained that vessel’s DP positioning system guided a USBL transponder on the tool which, along with a survey navigation screen set up in the Rotech control cabin, gave the company’s crew real time visibility of the tool’s location throughout the operation.
The tool located the cable using a tool-mounted sonar imager, securing it by its grab function and inspecting with an onboard camera and subsea lights, after which it was cut and recovered.
Operations were assisted by a client-owned remotely operated vehicles (ROVs) which provided a live video feed of the operations.
Stephen Cochrane , director of subsea at Rotech Subsea, said: ” Both cuts to the cable were completed in under 10 minutes and the efficiency of the operation, and in particular the combination of cutting and recovery in a single tool, saved the client a significant amount of time over other proposed methods to complete the scope.”
Rotech Subsea’s RSG-C tool can be used to carry out cable, umbilical and pipeline cutting and recovery, as well as rock removal and relocation.
To remind, the company secured a new contract in September 2022 after having completed a four-month cable de-burial and re-burial campaign at Saint-Nazaire, France’s first commercial scale offshore wind farm.