Installation of the 160 wind turbines for RWE’s Gwynt y Mor off-shore wind farm off the Flintshire coast in North Wales is now well underway with the last of the turbines due to become operational in 2014. When complete, the wind farm will supply enough electricity for 400,000 homes.

Crucial to the operation and maintenance of the new wind farm is a 110m long steel berthing pontoon provided by BAM Nuttall under a design and build contract. Beckett Rankine has been engaged as RWE’s technical advisor and design reviewer for the project. The new facility provides berths for eight off-shore wind farm support vessels, as well as space and facilities for efficient fuelling and loading operations.

As well as fuelling facilities, each berth is also supplied with electrical power and potable water supply. A loading crane on the north end of the pontoon is capable of loading objects up to 1,000kg on/off the vessels.

As the site is only semi-sheltered, key aspects of the pontoon are its stability and motion and roll characteristics which have been designed to maximise the operational window. Durability and minimising maintenance costs are also critical requirements as the facility which is required to remain in continuous use over its 25 year service life.

Moored by tubular steel piles arranged to facilitate berthing on both sides, the pontoon is located at a distance of 75m from the southeast end of the South Quay wall in order to provide clearance for construction vessels (JuBs, etc.) approaching Berth No1.

The pontoon is aligned parallel to the tidal flow and located in deep water (in excess of 3m at LAT) to reduce hydraulic impacts and to facilitate all-tide access. The berth is accessed from the quay via a fixed bridge and an articulated linkspan connecting an intermediate landing platform to the pontoon. As the site is next to a nature reserve the bridges and pontoons incorporate sight screens so that birds in the reserve are not distracted by the sight of people moving about.