Subsea inspections: Gwynt-y-Mor

James Fisher Marine Services completed a subsea inspection scope of works on the Gwynt-y-Môr Offshore wind farm in North Wales.

Gwynt-y-Môr Offshore Wind Farm was, at the time of construction, one of the largest wind farms in Europe, with enough power generation to produce electricity for 400,00 homes. Midway through 2015 James Fisher Marine Services completed a subsea inspection scope of works on the wind farm.

Gwynt y Mor Offshore Wind Farm Ltd consists of 160 WTGs off the coast of North Wales. They were installed between August 2012 and June 2014. As part of their ongoing maintenance requirements the Transition Piece (TP) and Monopile (MP) must be inspected.

This includes a subsurface inspection of the grout seal, anodes, steel work and general condition of the marine growth. In addition there was a separate visual inspection and sampling of the marine growth to assess the marine life.

On request of Dover Harbour Board, local companies and employment were to be utilised as much as possible. JFMS hired the Dover based work vessel Sealift III, used a local fabricator for the test pieces, anode jigs and replacement pad eyes and accommodated a dive team in a locally run hotel for the duration of the works, as well as local suppliers for ancillary items throughout the project.

The CP System was installed and designed by Corrosion Prevention Ltd and they also acted as the consultant to DHB during the project. The anode design was assessed by JFMS’s Project Engineer, Nadine Stanistreet, who then tasked Impalloy Ltd to supply the anodes as per the agreed design. Impalloy were chosen due to previous use of their high quality anodes and the fact they have the ability to manufacture to design specifications at short notice whilst maintaining quality.

After completion of the works a full written report was issued accompanied by a video survey of all welds and anode installations. Over 400 stills of the installed system, UT readings of the system weld locations and monopile itself were also issued.

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