Nearshore cable handling for offshore windfarm development

Benefits

• Versatile rental fleet provided three tensioner systems suited to cable and beach location
• Technical support and advice throughout the project
• Equipment with software capable of data logging all operations to ensure cable integrity
• One subcontractor to deliver complete solution

Challenge

• Hornsea One is to be the world’s largest offshore windfarm when commissioned
• The client was required to perform the shore approach to lay three cables from the CLV Ndurance cable laying vessel at 3.6km offshore to an onshore beach site
• Three cables were to be transferred from the vessel to the shore via a jack-up and two pontoons where tensioners were stationed
• Performance of each machine was to be logged to ensure cable integrity was not compromised. The work was required to meet a tight mobilisation schedule and timeline for completion.

Solution

• One 15Te tensioner was installed on a jack- up which involved designing some of the jack-up outrigger structure
• Two 10Te tensioners were installed on separate Linkflote pontoons which required design and supply of all the sea fastenings
• Manual and digital logs were taken for the activities during the pull ins with Sparrows PLC engineers implementing equipment upgrades to ensure data logging was performed
• Bespoke track pads were installed onto each of the tensioners with a special material to ensure higher friction was achievable and track pad to cable contact pressures were lower than the cables design limitations
• As well as supply of the tensioners, experienced Sparrows operators managed the equipment throughout the project.