VESSEL REFIT | Amazon – McDermott construction vessel upgraded to perform hex joint subsea installation

US-based McDermott International has resumed operations of one of its pipelay and construction vessels following its conversion in the Netherlands with the aim of equipping it for ultra-deepwater hex joint installation duties.

Dutch shipbuilder and engineering firm Royal IHC was selected to carry out the modernisation work on the construction vessel Amazon to enable it to perform its new role. Following the upgrades, the vessel is now capable of installing hex joints up to 60 centimetres in diameter on a worldwide basis.

The 654- by 105-foot (199 by 32-metre) vessel is operated by McDermott under a long-term bareboat charter that started in 2017. It is equipped with twin Huisman 440-ton (400-tonne) cranes with active heave compensation as well as the ability to operate in water depths of up to 8,202 feet (2,500 metres). Accommodations are available for 200 personnel.

The modifications consisted of removing the existing tower and replacing it with a fully enclosed J-Lay system with 1,653 tons (1,500 tonnes) of dynamic top tension on the tower, which will enable large subsea structures and hex sections of pipelines from 4.5 to 24 inches (11 to 60 centimetres) in diameter to be installed.

Other modifications include an integrated multi-joint facility, where single joints will be welded to form hex joints. The 11,023 tons (10,000 tonnes) of existing cargo space on board will remove the requirement for onshore facilities to produce the multi-joints, improving the vessel’s operational flexibility and reducing reliance on shore bases for support. The vessel can be deployed at major field development projects with rigid pipelay requirements at depths of nearly 11,482 feet (3,500 metres).

The vessel also boasts a 44- by 27-foot (13.5- by 8.3-metre) moonpool and two hangars equipped with launch and recovery systems for use by remotely operated vehicles.

The onboard operation processes are now highly automated for optimised safety performance and production efficiency. Royal IHC said this also results in a reduced number of staff requirements for process supervision.

Propulsive power is provided by three MAN 5,040kW generators and four MAN 4,480 kW units. These drive three Steerprop 3,500kW azimuthing stern thrusters as well as three 2,400kW forward thrusters and a 1,800kW tunnel bow thruster from Brunvoll. An average transit speed of 11.7 knots can be achieved.

Crew facilities include one- and two-person cabins, a gym, a game room, conference rooms, a library, an internet room, a sauna, a construction workshop, and customer offices. The vessel is also large enough to accommodate two rescue boats, eight 25-person liferafts, and four 100-person lifeboats, all equally split between port and starboard.

Amazon deployed to West Africa on its first project following completion of the conversion works.