The Isle of Man Ship Registry has flagged Subsea 7’s newest reel-lay vessel, Seven Vega
Seven Vega is the 11th OSV built for Subsea 7 to be flagged with the Registry and has been designed to install economical flowline technologies that address the growing market trend towards longer tie-back developments, and sets a new standard for offshore pipelay.
Isle of Man Ship Registry senior surveyor Chris Martin, who has been involved in nine Subsea 7 projects starting with the pipelay vessel Seven Oceans in 2006, said “the Registry is proud to have been part of yet another successful project. The majority are fully certified as special-purpose ships, predominantly designed for cable and pipe laying. They are fantastic vessels equipped with amazing technology and I feel fortunate to have played a role in so many of the builds.”
While most Subsea 7 vessels store piping and cabling in large carousel holds under deck, Seven Vega’s innovative design stows the product on external vertically mounted reels recessed into the deck with an open-top configuration. The design of the reel-lay system focused on crew safety, total product capacity, operational efficiency and flexibility. The twin tensioner pipelay tower tilts to allow pipeline installation from shallow waters to depths of up to 3,000 m. The large multi-level workstation optimises the efficiency of operations in and around the firing line, while the creative positioning of the main and auxiliary reels – recessed into the main deck – offers payload flexibility.
The ship’s unconventional design required close co-operation between Class and Flag to identify and achieve an equivalent standard of quality and safety compared to a traditional vessel.
Mr Martin and fellow senior surveyor Carlo Vinelli analysed the proposal against statutory regulations to ensure the design was safe and met relevant regulatory requirements. Mr Martin said “It was quite a challenging design and naval architects undertook a lot of work before the keel was laid to help get the novel design through the various regulations. Proving the design of the main reel holder was a particular challenge, requiring a number of tank modelling tests to ensure compliance.
Model seakeeping trials were carried out at MARIN’s facilities in the Netherlands to understand exactly how the vessel would perform in extreme operational sea conditions.”
“It was an exciting project to be part of – completely different, for example, to the construction of a standard bulk carrier that in some cases might be turned around in just three months. It took three years to get from kick-off to registration, which underlines just how specialist Seven Vega is and the level of technology incorporated into the build.”
A team from the Isle of Man Ship Registry will now carry out a post-registration inspection of Seven Vega, followed by general inspections every 2.5 years.
The Registry recently began offering remote general inspections to its clients where appropriate as shipowners are forced to contend with travel restrictions imposed due to the Covid-19 pandemic.
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