MAN B&W Diesel has been awarded the contract to supply complete twin-screw medium speed propulsion packages for six Anchor Handling Tug Supply Vessels (AHTS). The newbuildings, which will be built by Labroy Shipyard, Batam, Indonesia (Labroy Shipbuilding and Engineering Pte Ltd, Singapore) are to be operated by Swire Pacific Offshore Limited, Singapore. The first newbuilding is expected to be launched in the beginning of 2007, and the following vessels are planned to follow at two-month intervals. The 120-ton bollard pull AHTS vessels have been designed by the U.K.-based IMT Marine Consultants Ltd., with specific optimization for the worldwide operation of Swire Pacific Offshore activities.
A total main engine output of 2 x 3,285 kW will supply the propeller thrust, for a bollard pull of more than 120 metric tons. The ship service speed is optimised for 13.5 knots. The MAN B&W Diesel twin-screw Alpha Propulsion System type 9L27/38-VBS, which has been specified for the newbuildings, include:
• Main Engines Two MAN B&W 9L27/38 engines, fitted with full engine power PTO and integrated journal bearing at the front-end, driving a fire-fighting pump arrangement.
• Reduction Gearboxes Two MAN B&W Alpha AMG55 gearboxes, type 57VO55EV, with a speed reduction ratio of 800:141. Additionally, each gearbox is equipped with a 1,800 r/min PTO shaft for a 1600 kVA shaft alternator.
• Propellers Two MAN B&W Alpha type VBS980 four-bladed controllable pitch propellers. The 3,800 mm ducted CPP systems are complete with tail, intermediate shafts and bearings, stern tube equipment, and MAN B&W fixed propeller nozzles type AHT.
• Control System In addition to the engine room control station, the Alphatronic 2000 Monitoring, Control and Safety System includes a main bridge control station and an aft bridge slave control station. The propulsion control is interfaced to a Joystick/Dyn Pos System, which manages the overall ship maneuvering via gyro compass, rudders and thrusters.