Specialised vessels are necessary for the efficient transfer of personnel between shore and sea-based facilities. Over 300 specialised vessels are in operation around the world, bringing technicians to and from work on offshore arrays. Although more general boats can be used and will be in the early days of the US industry, there are considerable advantages to creating dedicated vessels.
Most designs are aluminium or composite materials, with speeds of 15-30 knots and propulsion either by propeller or water jets. With two crew and 12 passengers, the vessels can carry the personnel in comfort to the work site. Some deck cargo space is available for storage of tools, supplies, equipment and spares for the team to deliver or utilise in maintenance. Effective docking methods are important to transfer the personnel easily between ship and turbine are the main difference between these types and more conventional boats. The restriction on 12 passengers is because of "passenger shipping" regulations which set that as the upper limit before more extensive legal compliance is required (and thus higher operating costs).
One particular advantage of specialised vessels is improved gangways to better transfer crews to their workplace, including advanced “Walk to Work” systems of crew transfer. Uptime International sales and business development director Bjørnar Huse said the level of performance expected of gangways is evolving all the time.
“Gangways are getting bigger, they are capable of lifting more equipment, but the main focus of development now is on automation and using ‘intelligent gangways’ that are less dependent on a ‘man in the loop’ to operate them. “A computer can handle anomalies and make gangway operation safer, more reliable and dependable,” he said.
Service Operation Vessels (SOVs) And Crew Transfer Vessels (CTVs)
As the European market for SOVs and CTVs evolves a market for both vessel types is also emerging in the US, and one of the leading designers and builders of crew transfer vessels in Europe has unveiled a new design aimed at the offshore wind market in the country.
Damen Shipyards Group’s new design, the fast crew supplier (FCS) 3410 service accommodation and transfer vessel, is derived from its existing series of Twin Axe bow designs. The Axe Bow is a patented design that allows the ship to ‘cut' through waves instead of slamming, providing improved seakeeping and onboard comfort.
The FCS 3410 further develops the Axe Bow and Damen Fast Crew Supplier concept, tailoring it to meet the requirements of the US market, as Damen sales manager US Daan Dijxhoorn explains,
“This vessel is well suited to numerous markets, however, we have given it long endurance capability so it can remain at sea for up to five days at a time – a requirement typically seen in US operations. To facilitate this, we have designed a vessel 6 m longer than previous FCS types, able to host more onboard personnel and accommodation."
Numerous design features of the FCS 3410 vessel ensure its suitability for operations in the developing North American offshore wind market.
The vessel will be built on location in the US and is an improvement on existing Damen designs which have proved to be well-liked by crews and cost-effective for operations.
Daan Dijxhoorn continues, “This vessel is well-suited to numerous markets, however, we have given it long-endurance capability so that it can remain at sea for up to five days at a time – a requirement typically seen in US operations.
“To facilitate this, we have designed a vessel six metres longer than previous FCS types.”
The US OW Market is projected to be around $24 billion by 2024. With seaborne operations costed at 3%, this would mean approximately $1 billion of investment in the area, which is a large sum and would support a modest domestic fleet of SOVs and CSVs, especially if these were multi-purpose and could service the O & G industry as well.
The market is not limited to specialised vessels – feeder barges, tugs and a variety of other ships, including cable layers and fishing boats can be used depending on the task required and their availability. The current generation of jack-up installation vessels is built to service 9 MW and larger wind turbine installations and water depths of more than 40 metres. It is expected that even bigger craft will be needed for the planned turbines such as GE's Haliade-X 12 MW turbine with its 260-metre total height.
Heavy Lift Vessels will also be required for the most massive turbines and to install or later remove the very large loads of offshore wind AC/DC converter stations. The market will also likely need Multi-Purpose Project Vessels to provide services such as towage, anchor handling, survey and dive support and suchlike. With larger wind arrays being created offshore in the 2020s, it is possible that Accommodation Vessels might be needed to house crews in comfort for prolonged deployments.
The requirements of the Jones Act mean that specialised vessels will have to be US-built, owned and crewed, but the act does not require US designs, so ships like the Damen FCS 3410 and others could directly be built in US shipyards as the market matures.
Numerous project vessels will be needed to service the burgeoning supply chain for the US market. Owing to the exigencies of the Jones Act most of them will have to be built in the US. However, these will likely be existing designs, or minor modifications, such as increased range – there will be no need to reinvent the wheel and existing shipbuilders will undoubtedly licence their I.P. or expertise to US companies to expedite the creation of a service fleet. Most of the vessels will also be compatible with the requirements of the Oil and Gas industry to maximise potential charter opportunities.
Each year, project leaseholders, policymakers and supply chain players meet at the US Offshore Wind 2019 conference (June 10-11, Boston) to discuss matters relating to project development and supply chain expansion. It has become the world stage for the US offshore wind power industry and the premier networking destination for businesses that are looking to secure market share. If you want to invest, find partners, develop projects or enter the supply chain – the event has it all covered in just two days.
2000 delegates attend each year, from Active market players to New market players, including developers, financiers, legal, policymakers, EPCI’s, OEM’s, Vessels (design, construction and operations), shipyards, fabricators, geoservices, component manufacturers and technology providers. Click here to read the event brochure.