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Encyclopedia of Marine and Energy Technology

Subsea Construction Vessel BOA DEEP C


According to Ship and Boat International July/August 2004 and Significant Ships of 2004

Built in China at Jin Ling shipyard, and outfitted in Spain at Factorias Vulcano shipyard, BOA DEEP C is believed to be the world largest construction vessel. The vessel was designed by the well-known Norwegian consultancy Vik-Sandvik (now Wärtsilä Ship Design) for operations in the subsea market, tackling mooring systems, pipelines repairs, template and anchor installations. Particular benefit is derived from the vessel’s ability to work at previously inaccessible sea depths of up to 2000m. 

The deck area measures 1150m2, and is reinforced for a specific load of 15t/m2. It is served by two off shore heave-compensated cranes; 250t/13m and 30t/13m, and two cranes knuckle boom type with SWL of 15t/20m, 1 x 8.4t, and 1 x 6.3t marine cranes. A deepwater towing/ anchor handling winch with a 500t line pull is provided, whilst the stern roller has a downward pull of 750t and a bollard-pull rating of 260t.The mooring and anchoring equipment includes two mooring winch/windlasses forward and two capstans aft, with various tugger winches, guide winches and powered guide pins also installed. BOA DEEP C also boasts twin built-in deepwater ROVs of Oceaneering Millenium type and a 7.2mx7.2m moonpool. The ROVs are located in hangars. Over the side a guided launching system for extreme condition operation is provided.

A very interesting feature of the vessel is the propulsion machinery designed to operate in three modes according to the operational requirements, these being diesel-mechanical for steaming; diesel-electric for use in DP mode; or diesel-mechanical with electric booster for maximum power in “bollard-pull mode”. The machinery is based on six 3600 engines: a pair of V16-cylinder units on the main shafts, and two eight-cylinder and two six-cylinder models used as genset drives.

Each of the two engines is rated at 6000kW and drives a four-bladed 4.4m-diameter CP propeller in a nozzle via a ACG1080 gearbox, the direct-drive arrangement being used when steaming. For maximum bollard pull, the power on each shaft can be boosted by 3000kw from a Siemens combined PTI/PTO (electric motor/shaft alternator). A dieselelectric mode is used for DP operations, and positioning requirements are met by four 1425kW tunnel thrusters (two aft and two forward) and a 1200kW retractable azimuthing thruster located abaft the forward bow thruster.

Length, oa: 119.30m, Length, bp: 102.00m, Breadth, mld: 27.00m, Depth, mld: 11.60m, Draught design: 8.80m, Deadweight: 8492dwt, Lightship mass: 9493tonnes Service speed: 13.00 knots. Output 2x6000kW.

Subsea Construction Vessel BOA DEEP C