23 kms off the Dutch coast between the cities of Zandvoort and Noordwijk lies the 129MW Eneco Luchterduinen windfarm. It generates clean electricity for nearly 150,000 households. Global engineering specialist Van Oord was contracted to design, procure, and construct the wind farm. One of the major transportation issues the project faced was the ability to safely transport the 50 metre rotor blades that would power the turbines.

The materials were to be delivered aboard “Aeolus”– a 140-metre-long transport and installation vessel built in Germany. In total, 129 rotor blades were required, each heavy and oddly shaped, thereby posing unique securing and lashing challenges.

In anticipation of the difficulty of transporting these rotor blades, Van Oord involved RUD early on in the transport planning process.

There were a number of special conditions that needed to be fulfilled in order to make the job a success. The rotor blades had to be transported using a special steel frame called a “rack,” which was mounted on the transport surface of Aeolus. This rack could carry 24 rotor blades at a time. The fully loaded rack was to be transported on every trip, alongside eight towers and machine houses. At each of the 160 force transmission points, the lashing equipment had to have a strength of LC=10,000 daN (lashing capacity).

At the centre of the solution was the RUD ICE Grade 120 lashing chains system using 10mm chains, tensioning elements and end lifting and shackle componentry.

A combination of this tried and tested system and UHMWPE ropes were utilised in order to address an issue resulting from enormous clamping lengths of more than 20 metres.

The bottom two-metre-long end is where the main handling (shortening and tightening) takes place, and the ICE system offers particular advantages here. As the 10-millimetre ICE system is 40% lighter than the standard system, and ICE’s precise shortening capabilities enabled by links in 30-millimetre steps reduced the time for pre-tensioning considerably.

The long end was secured using UHMWPE ropes. These efficiently performed the task of transferring the retention forces securely and cost-effectively, with little weight and low stretching, leading to a successful project execution.

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