Seven Borealis

A monohull pipelay/heavy lift vessel equipped for both S-lay and J-lay in all water depths and installation of the heaviest subsea production structures in ultra-deep and deepwater projects in the world's harshest environments. The revolving mast crane is capable of lifting 5,000 t (at 40 m) over the stern.

Built by

Sembawang Shipyard Pte. Ltd, Singapore



Owned by


Designed by

Ulstein Design & Solutions B.V.

Ordered by

Nordic Heavy Lift

Operated by


IMO Number


Principal dimensions

182.2 m
46.2 m
Speed (max):
12 kn
399 POB
Deck area:
730 sqm

Note: Subject to selected variant configuration


Fuel oil:
3080 cbm
64 cbm
Fresh water:
1,123 cbm
Ballast water:
20,600 cbm
Technical water:
700 cbm
Revolving mast crane:
5,000 t
Mast crane, max waterdepth:
-6,000 m
2 knuckle-boom cranes, each:
40 t
Pedestal mounted crane:
36 t
J-lay tower:
1,000 t
S-lay system:
600 t
On-board pipe storage:
2,800 t
Work-class ROVs:
2 x



Ship history

Seven Borealis was designed as heavy lift vessel, and converted in pipelay (or deepwater construction) vessel. Based on the SOC 5000 design from Ulstein Design & Solutions B.V.

2009: The vessel was first ordered by Nordic Heavy Lift and launched from Nantong Yahua shipyard in China 19 October 2009. The hull was towed to Singapore for final outfitting at Sembawang. Later, the hull was acquired by Acergy, now merged with Subsea7. Originally ordered as a classical, heavy-lift vessel, Subsea 7 decided to convert the 'Seven Borealis' to a pipelay and heavy-lift vessel with Ulstein's assistance. The mast crane was complemented by an existing J-lay system transferred from a Subsea 7 vessel; a new S-lay system and at a future point, a 500t flex-lay tower for vertical laying. The new vessel would also feature a range of support and construction equipment configured for global deep water and harsh environment operations. The conversion involved adding 1,000 km of cables to the vessel.

2012: The vessel arrived in the Netherlands in April 2012 for final outfitting of the pipelay system. End of September 2012 the vessel left for her first job, Total's CLOV project in Angola block 17. The program included J-lay of 40 km of pipe-in-pipe production flowlines, S-lay and J-lay of 32 km of gas export lines and 60 km of water injection lines, and installation of a gas export single hybrid riser and associated manifolds.

In November 2012, Subsea 7 announced a contract from Total E&P Norge for the development of the gas field Martin Linge in the North Sea. Seven Borealis was set to install the 70 km gas export pipeline.

2013: The vessel was nominated Ship of the Year (2012) by Offshore Support Journal.

January 2021: The Seven Borealis in operation outside Cape Town. Photo: Michael Kovensky.
January 2021: The Seven Borealis in operation outside Cape Town. Photo: Michael Kovensky.

Please contact us for more information

Ulstein Design & Solutions B.V.

Cornerstone Building (6th floor)
Rotterdam Airportplein 32
3045 AP Rotterdam
The Netherlands

Tel: +31 10 475 00 11