Tuesday, March 9, 2021

New Launch System for Work Boats and ROVs at Sea Replaces Conventional Davits

Design Intended to Eliminate Some Bad Weather Problems
Shipping News Feature

NORWAY – Boat launch specialist Vestdavit is making big claims for its latest innovation, the company's MissionEase system which enables multiple boats to be moved around on the mission deck and safely launched from either side of a mother ship, even in rough weather.

The initial fitting is to the new build cable-laying vessel Nexans Aurora, currently under construction at Norwegian shipyard Ulstein Verft. The DP3 vessel, with a cable capacity of 10,000 tonnes, will perform cable-laying, cable system protection and trenching for Nexans Subsea Operations, and its first contract will entail installing export cables for the Seagreen wind farm project off Scotland following her launch.

Instead of a traditional davit mounted on the upper deck of a ship, MissionEase uses a system of hydraulic cradles to move boats on a tracking system within a hangar inside the hull to positions for maintenance, preparation or launch using a telescopic davit. The innovative system installed on the Aurora will have capacity to handle as many as 14 craft, including workboats and ROVs, that can be securely stored and mobilised in the enclosed ‘garage’ on the mission deck.

These will be used to carry out vital maintenance and other work on submarine cables for power supply and fibre-optical communication connected to offshore installations. The MissionEase system avoids the risk of shifting weight loads when lowering and lifting boats in adverse weather conditions using a traditional gantry davit on the top deck where space was also limited on the Aurora due to the density of cable-spooling equipment on board.

Such a system gives the cable-laying vessel a wider operational window so it can continue working on time-critical offshore installation work, avoiding weather-related delays that can have a costly knock-on effect for the client in terms of stalled projects. A boat-launch system is an essential part of the complex jigsaw puzzle for such a new build and among the many components that have to be delivered on time and with the correct specifications to ensure timely delivery of the vessel from the yard.

Supported by digital 3D modelling work to eliminate anomalies, Ulstein Verft’s senior engineer responsible for outfitting engineering, Arild Brevik, says the main challenge for the yard in installing MissionEase was ‘a lot of measuring’, continuing:

“Measurements have to be constantly checked to ensure everything fits and works together, accounting for structural supports above and below the mission deck.”

While Vestdavit has previously delivered a scaled-down version of the MissionEase for an Esvagt crewing vessel, this will be the first time the full system has been installed on a new build. The Nexans Aurora is on track for departure at the end of May following scheduled final testing earlier the same month.