CAT link refurbishment on BorWin beta

An unplanned height difference between the connection points created additional loads on the existing CAT connection between the topside and the cable access tower. Rod ends and double joints were overstressed under extreme loads; deformations that had already occurred could have led to further loads and reduced fatigue strength. The connection needed to be replaced promptly.

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The remediation had to be carried out on an operational platform. Access, load bearing, and component handling were spatially restricted – at the same time, the replacement had to ensure no uncontrolled load conditions were created on the existing structure.

01 · Planning the remediation

Method statements, personnel and offshore workflow planning, as well as quality and inspection documentation structured the project. The remediation solution provided for the new connection to be placed at a lower, permanently load-bearing position.

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02 · Manufacturing the new connection

Two new horizontal rod elements with articulated end connections were manufactured, tested, and prepared for offshore transport.

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03 · Setting up the work area

Scaffolding, lifting points, chain hoists, and material transport were arranged to allow for the controlled movement of old and new components within the confined space.

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04 · Replacing the old structure

The damaged connection was secured and dismantled. Subsequently, the new CAT link was lifted into place, positioned, aligned, and welded.

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05 · Inspection and long-term protection

Surveying, welding supervision, and non-destructive testing confirmed the quality of the execution. The coating restored corrosion protection for the demanding offshore climate.

• Work on a structurally critical connection during ongoing platform operations – with load paths controlled at all times.
• Welding, scaffolding, surveying, coating, and NDT services in a single workflow.
• New connection for the targeted 30-year service life.
• Acceleration measures during execution.

The new CAT link was installed, tested, and coated. According to the project review, work began on August 13, 2018, and was completed on October 22, 2018 – one week ahead of the original schedule.

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No technical deviations were documented regarding tools, materials, qualifications, or the work steps performed.