New reel-lay vessel Seven Vega launched in the Netherlands will join fleet in 2020
New integrated reel-lay vessel Seven Vega is company’s first to be contracted with IHC to include pipelay system
For centuries, sailors have used the positions of the sun and stars to navigate in the open sea. Starting in 2020, subsea engineering and vessel owner Subsea 7 will have its own ‘star’ to guide it into the future when it welcomes into its fleet Seven Vega, a new reel-lay vessel engineered, designed and under construction by Dutch shipbuilder Royal IHC.
While Seven Vega will be the ninth vessel built by IHC to join Luxembourg-headquartered Subsea 7’s fleet, it is a significant development in that it is the first time the contract with IHC also includes the pipelay system.
At its launching at Royal IHC’s shipyard in Krimpen aan den IJssel, the Netherlands, in May, Subsea 7 executive vice president strategy and commercial Stuart Fitzgerald called the vessel “an important investment for the future.” Seven Vega “has been designed to deliver flowline technologies that address the growing market trend towards longer and more complex tie-back developments”, said Mr Fitzgerald. “The vessel’s cutting-edge pipelay system focuses on crew safety, operational efficiency and flexibility. This system will be capable of installing complex rigid flowlines including pipe-in-pipe systems and electrically heat traced flowlines in water depths up to 3,000 m.”
When the letter of intent was signed to build the Seven Vega in September 2017, the company knew it wanted to get Subsea 7 employees involved in its naming. The name was chosen from among 1,700 entries submitted by Subsea 7 employees in a contest.
“It was important for us to involve our employees in the journey of our newbuild vessel”, says Mr Fitzgerald. “We chose Seven Vega because Vega is one of the brightest stars in the northern sky and will become the North Star in the future. We look forward to welcoming the winner of the competition to the naming ceremony and to Seven Vega joining the fleet in the first half of 2020.”
As with the previous nine vessels built by the Dutch yard for the UK-based OSV owner, Seven Vega represents close co-operation between Royal IHC and Subsea 7.
“The integrated approach of IHC to vessel design will give Subsea 7 an industry-leading asset that sets a new standard in offshore pipelay”, says Royal IHC chief executive Dave Vander Heyde.
Efficient design yields compact platform
A fully integrated reel-lay vessel, Seven Vega’s compact dimensions are due to the creative positioning of its three enginerooms and main reel, efficient use of the superstructure, and low air draft pipelay tower, said Subsea 7. The design opens up a large aft working deck, while the optimised mass distribution minimises the ballast water requirement.
Seven Vega has an overall length of 149.2 m, breadth of 33 m, depth of 13 m and draught of 8.3 m, accommodation for 120 (in four suites, 42 single cabins and 37 double cabins) and dynamic positioning (DP) class 3 capability.
“We chose Seven Vega because Vega is one of the brightest stars in the northern sky and will become the North Star in the future”
The DP system, provided by Kongsberg, comprises three differential GPS units, two high-precision acoustic positioning units, a taut-wire sensor, a hydroacoustic position reference system and a RADius relative position reference system.
Its reel-lay system has a 600-tonne top tension capacity consisting of a 32-m main reel and a 17-m auxiliary reel with a maximum storage capacity of 5,600 tonnes and 1,600 tonnes, respectively. Seven Vega will have a Huisman active heave-compensated main crane with a lifting capacity of 250 tonnes. Alongside this, the vessel will be fitted with an active heave-compensated auxiliary crane with a 50-tonne capacity, another auxiliary crane with a 15-tonne capacity and a ramp-top crane with a 20-tonne capacity. All auxiliary cranes, as well as the main crane’s whipline, are certified for man-riding operations.
The vessel’s two side-launching work-class Perry XLX-EVO ROV systems from Houston-based Forum Energy Technologies are rated to operate in depths down to 3,000 m. The XLX-EVO is a fully integrated survey system capable of interfacing with all modern survey equipment, including sub-bottom profilers and multibeam sonars.
The vessel’s twin tensioner pipelay ramp tilts to allow pipeline installation from shallow waters to depths of up to 3,000 m. The large multi-level workstation optimises efficient operations in and around the firing line, while having the main and auxiliary reels recessed into the main deck offers payload flexibility.
In addition, the all-electric main crane allows lift parameters to be adjusted promptly without manually adapting the active-heave system. By having fewer components, maintenance and energy consumption are also reduced.
Propulsion power will be supplied by six main engines and six diesel generators from Hyundai. There are three 3,500 kW and three 4,000 kW engines giving a total installed power of 22.5 MW. There are three independent enginerooms. Manoeuverability and station keeping is supplied by a Wärtsilä propulsion package of three 3,200 kW stern-mounted azimuth thrusters, two 2,400 kW retractable bow-mounted azimuth thrusters and two 2,200 kW bow-mounted tunnel thrusters. The reel-lay vessel will have a service speed of 13 knots and a maximum bollard pull of 100 tonnes in DP3 failure mode.
Production and fit of the vessel’s integrated electrical and nautical systems was performed by Rotterdam-based Croonwolter&dros and Sliedrecht-based Bakker Sliedrecht. Croonwolter&dros focused on the low-voltage installations, and Bakker Sliedrecht handled high-voltage installations and drive systems. The scope of the contract includes three 6.6 kv main switchboards, three 440 v auxiliary switchboards, seven water-cooled electrical drive systems for the thruster system, motors for the thruster system, DP design in accordance with Lloyds AAA notation requirements, alarm, monitoring and control systems, navigation and communication equipment, main power supply for all mission equipment, complete lighting installation and complete cable installation and connection.
Due to the positioning of the enginerooms, main reel and superstructure space usage, the vessel has a large main deck of approximately 800 m2, with a strength of 10 tonnes per m2.
Storage tanks can hold 2,900 m3 of marine gasoil, 725 m3 of potable water, 3,900 m3 of ballast water, and 1,680 m3 of fresh water. There is 1,200 m3 of heeling/stabiliser tank capacity.
To carry out pipelaying duties, the vessel will be fitted with two reels. The main reel has a maximum storage capacity of 5,600 tonnes, and will be capable of stowing products ranging from 4 to 20 inches in diameter. The secondary reel has a storage capacity of 1,600 tonnes. The upper tensioner has a 162-tonne capacity, the lower tensioner a 318-tonne capacity and the back tension is 130 tonnes, making for a total maximum dynamic top tension of 600 tonnes.
The vessel is also fitted with two 325-tonne abandonment and recovery winches, which can be used in a combined mode to recover a catenary weight of 650 tonnes. Other features include a ramp angle of 45-95°, capability for piggyback direct electric heating and rigid systems, flexible pipe top tension of 210 tonnes, a 21-m aligner diameter, a 75-tonne spooling-on tensioner, a twin-level workstation and 14-inch by 18-inch pipe-in-pipe straightening capability. The system will also be able to deploy pipeline end terminals measuring 5 m by 5 m by 10 m.
Seven Vega’s helideck will be approved for usage by Airbus Helicopters’ H225 Super Puma and Sikorsky’s S61N, S76 and S92 helicopters. It will incorporate a Kongsberg HMS 100 helideck monitoring system, which analyses helideck motion during landing operations to increase safety in rough weather, tracking helideck attitude and vertical velocity, wind speed and direction, air temperature and barometric pressure.
Classed by Lloyd’s Register, the vessel has notations including crew accommodation comfort of CAC(3), Winterisation H and D, covering materials for hull construction and direct design of -30, and an Ice Class of 1D. It also holds the ECO notation, meaning that its construction and operation exceed current statutory environmental requirements in the maritime sector.
Seven Vega will also be compliant with IMO’s Code of Safety for Special Purpose Ships, which recommends design criteria, construction standards and other safety measures for so-called special purpose vessels, ie vessels that carry more than 12 persons in addition to the crew, that are not passenger craft, and that exceed 500 gt.
SEVEN VEGA AT A GLANCE
Owner: Subsea 7
Builder: Royal IHC
Class: Lloyd’s Register
Length, overall: 149.2 m
Beam: 33 m
Depth: 13 m
Draught: 8.3 m
Clear deck area: 800 m2
Deck: Strength: 10 t/m2
Main engines: 3 x 3,500 kW
Generators: 3 x 4,000 kW
Main crane: 250 t, 3,000 m, AHC
Main reel: 5,600 t
Secondary reel: 1,600 t
Subsea 7 supports tie-back project in North Sea
Seven Arctic transported two 300-tonne templates for installation at the Nova field
Subsea engineering company and OSV owner Subsea 7 supported the installation of two subsea templates for the next phase in the development of the Nova oil field. Some 65 km of pipelines must be laid in preparation for tie-back to the nearby Gjøa platform in the Norwegian North Sea.
The Nova oil field is being developed with two subsea templates tied back to the Neptune-operated Gjøa platform. Gjøa will receive the well stream and provide water injection and gas lift to the Nova field. A new module will be lifted onto Gjøa in 2020.
Subsea 7’s construction and pipelay vessel Seven Arctic sailed the two 300-tonne templates 45 kilometers from the base in Florø to the Nova field, before craning the structures 370 metres below the ocean surface. The templates were constructed by Aker Solutions in Egersund, on the west coast of Norway.
Dynamic positioning class 3-capable, Seven Arctic is equipped with a 1,000-tonne capacity Huisman active heave-compensated offshore crane that has multiple modes of operation for topside and subsea lifting, including over its stern and starboard side.
The Nova field is operated by Wintershall Dea, formed by the merger of Wintershall and DEA in May, which holds a 45% share. Other project partners are Capricorn Norge AS, a subsidiary of Cairn Energy PLC, which has a 20% stake, Spirit Energy Norge AS, which has a 20% share, and Edison Norge AS, with a 15% interest.
“With the installation of these two templates we have successfully begun the subsea campaign for 2019”, said Wintershall Dea Nova project director André Hesse.
Nova is located in the Norwegian North Sea, 120 km northwest of Bergen. The expected recoverable reserves from the field are around 80M barrels of oil equivalent (boe), of which the majority will be oil. The partnership is investing almost US$1.2Bn in the development of the Nova field, which is expected to come on stream in 2021.