High spec subsea vessel joins Technip fleet

Two years ago, the offshore construction vessel North Sea Giant won OSJ’s Support Vessel of the Year Award. Now, the company has taken delivery of another high spec subsea vessel, North Sea Atlantic, which, like North Sea Giant, is working for Technip.

Designed especially for operation in deep water and in severe weather conditions, the ST-261 CD design from Norwegian naval architects Skipsteknisk has a high level of manoeuvrability and station-keeping capability and is outfitted and prepared for a range of duties. These include:
• pipelaying or cablelaying from carousels using a vertical lay system and moonpool or over the stern

• remotely operated vehicle (ROV) operations such as route survey

• subsea installation work through the moonpool and over the ship’s side

• crane operations for the positioning of modules on the seabed.

Completed by NorYards in Norway, North Sea Atlantic is the first vessel of ST design for this particular owner. The naming ceremony took place at NorYards in Bergen on 27 July. Now at work under the long term charter with Technip, the vessel’s first job saw it complete a 440-tonne heavy lift on Statoil’s Åsgard field on the Halten Bank in the Norwegian Sea, approximately 200km offshore mid-Norway.

The ST-261 CD is intended for worldwide operation and is fitted with a 550-tonne offshore crane and 2,000-tonne underdeck carousel and has accommodation for 120 persons and significant deck space – the free deck area is 1,950m2. The vessel is 141.6m overall, has a breadth of 27m and a draught of 11.5m.

North Sea Atlantic has a diesel-electric propulsion plant consisting of four generator sets (each of 4,200kW), two main azimuth propellers aft (each of 4,500kW), two tunnel thrusters forward (2,200kW each) and two retractable azimuth thrusters forward (2,000kW each). The DP standard dynamic positioning system on the vessel is a dual redundant system (AUTRO/DP3) with two acoustic positioning units (HIPAP with extended poles), a HAIN hydro-acoustically aided inertial navigation system with heading outputs, two differential GPS, a Seapath 300, Radius 1000 system with four antennas and three motion reference units, complemented by tautwire winches/A-frames.

North Sea Atlantic has a helideck for a Sikorsky S-92/S-61 aircraft or similar that complies with CAA CAP437/DNV/NOR BSL D 5-1 rules. Apart from the 550-tonne crane, the vessel also has a 50-tonne/15m active heave compensated offshore crane, an auxiliary crane, four capstans, each of 5 tonnes, two cranes for provision handling, hangars for port and starboard launching of work-class ROVs and ROV workshops and maintenance areas, along with the online/offline rooms, control room, offices and meeting rooms one would expect to find on a vessel of this type. The moonpool measures 7.2m x 7.2m and is strengthened for pipelaying and a module-handling tower.

Technip announced in 2012 that it had signed a long term charter agreement with North Sea Shipping for the newbuild construction vessel, and over a two-year construction period, teams from both companies worked together closely to ensure the project was delivered on time and as per the specifications. Designed to meet Technip’s specifications, the vessel is also capable of undertaking inspection, maintenance and repair (IMR) projects.

Technip describes the design as “meeting the highest requirements for subsea work”, and although it will work predominantly in the North Sea, the vessel is also suitable for deepwater operations worldwide. Having completed its first assignment working in the Norwegian sector of the North Sea, the vessel is due to undertake a number of other projects in the Norwegian sector, followed by projects in the UK North Sea.

Hallvard Klepsvik, CEO of North Sea Shipping, said the company was confident that the vessel would fulfil Technip’s expectations and that it would be a valuable asset for its future operations. David McGuire, vice president of Technip’s marine operations organisation, said he was “delighted” that North Sea Atlantic was joining Technip’s fleet of specialised vessels. Technip has taken a five-year charter on the vessel with an option to extend the contract. OSJ