When global subsea solutions specialist, N-Sea Group needed a reliable partner for its critical cable repair project in the Irish Sea, they turned to Red7Marine for a turnkey solution. With complete delivery of two jack-up barges, supporting tugs, a 220t telescopic crawler crane, accommodation and catering service, Red7Marine’s end-to-end package enabled N-Sea to focus on its project goals of completing the repair, safely and efficiently under a tight programme.
N-Sea Group was contracted by an Offshore Electricity Transmission (OFTO) to complete the repair of an export cable in the Irish Sea. In total 950m of submarine cable has been replaced, 400m off the beach at a challenging shallow water location with a large tidal range.
Cable installation and an offshore repair joint have been executed from Red7Marine’s Haven SeaSeven 400t jack-up barge. With involvement in the early stages of N-Sea’s bid, Red7Marine’s in-house team fabricated bespoke temporary works for the project to execute the cable installation and jointing works, and modifications were made to one of the company’s existing cantilever platforms to support the jointing habitat and cable chutes
Red7Marine’s 250t Haven Seariser jack-up barge acted as the accommodation and cable reel storage/spooling platform, working adjacent to the Haven SeaSeven with gangway access between the barges. Nine accommodation modules and welfare facilities were installed onto the deck of the Haven Seariser, enabling 28 crew to live on board the jack-up whilst the repair took place. To facilitate the modules and 106t cable reel, Red7Marine’s engineers designed and fabricated grillages, mezzanine deck infrastructure and various sea-fastenings.
Both barges had recently completed long term charters in Germany and were towed from Red7Marine’s headquarters in Ipswich to Vittoria Dock in Birkenhead for mobilisation ahead of the project taking place.
Kristen Branford, Managing Director at Red7Marine comments: “We take immense pride in being a dependable partner for our clients, especially when facing complex challenges. Working with the N-Sea team in the initial stages of the bid, we devised a methodology utilising two assets, with our engineers handling all feasibility, floating and jacked stability, leg penetration assessments and RAMS. It was great to push the capabilities of the barges and end with a solution that worked for N-Sea and the project requirements.
Providing an integrated marine support package inclusive of support tugs, a 220t telescopic crawler crane, accommodation and crew, enabled our client N-Sea to focus on their project goals in completing the repair, safely and efficiently under a tight programme.
We hope to support N-Sea again in the near future.”
The repair works were completed within three weeks, with the barges returning to the Port of Mostyn for demobilisation.
Dale McDonald, Operations Manager Subsea Cables comments: “When preparing and executing such complex projects as Principal Contractor, your supply chain and trusted Contractors play a vital role. Our dealings with Red7Marine have been positive throughout. Always willing to go above and beyond, to ensure the success of the project. The team at Red7Marine understood the complex nature of the scope and environment and were always quick to work with our project team to overcome challenges and find solutions.
We thank the Red7Marine for their support and commitment in supporting this project. ”
