Propulsion package for advanced trawler

14 Jul 2011
The original 2006-built 'Cattleya' - powered, like its successor by a MAN medium speed propulsion package

The original 2006-built 'Cattleya' - powered, like its successor by a MAN medium speed propulsion package

A Danish newbuild trawler will be equipped with a MAN Diesel & Turbo propulsion package, based on the L27/38 engine, following in the footsteps of the vessel it replaces.

The 4,000bhp propulsion package will include main engine and box coolers, reduction gear with hydraulic shaft brake and a 1,800kW PTO and shaft alternator, propeller shaft line, sterntube, propeller and propeller nozzle – together with a complete propulsion control and safety system with manoeuvring stations for four bridge positions.

Esbjerg-based owner Flemming Pedersen will take delivery of the new Cattleya in 2012; the ship will carry the same name as, but is a larger and more advanced vessel than its predecessor. Its length oa is growing from 62.6m to 69.9m, and with 1.4m additional width the tonnage increases from 1,337 to 1,750. Latest equipment is fitted, and up-to-date design solutions are employed.

The L27/38 powered package might appear to be a repeat from the current vessel, but the nine-cylinder 2,999kW Tier-II engine will be coupled to an AMG55 (Alpha module gear) gearbox with a reduction ratio of 800:119rpm for a larger and more efficient 4.2m ducted CP propeller. The new AHT (Alpha high thrust) propeller nozzle has been specified for ‘headbox’ mounting, with the aft ship design, propeller and nozzle optimised in cooperation with the builder, the Danish Karstensens shipyard. Such optimisation is expected to result in lower fuel consumption, with a carefully determined compromise between high-speed steaming and maximum pulling power efficiency at trawling speed with suppression of cavitation and noise.

As a result of the vessel’s ‘floating frequency’ system (from 60 to 50 Hz), the propulsion system is able to operate in ‘shaft alternator mode’ with reduced engine and propeller speed. With this part-load optimisation feature, offering up to 16.7% lower engine/propeller speed, the fuel consumption can be further reduced. Additionally, the electrically-driven retractable 800kW azimuth thruster can be deployed for low-power propulsion, standby, take-home and manoeuvring modes.

Cattleya - main data
  • Yard Karstensens Shipyard, Skagen, Denmark
  • Yard number 420
  • Delivery October 2012
  • Owner Cattleya A/S, Flemming Pedersen, Esbjerg, Denmark
  • Length oa 69.6m
  • Width 14.2m
  • Dept 8.70m
  • Gross tonnage 1,750
  • Speed 16 kn (estimated)
  • Bollard pull 68 tons (estimated)
  • Engine MAN 9L27/38, Power 2,999kW at 800rpm
  • Reduction gear MAN Alpha AMG55 Type 67VO55, Reduction ratio 800:119
  • Propeller MAN Alpha CPP, Type VBS1080-ODG, Diameter 4,200mm
  • Propeller nozzle MAN Alpha AHT Type FD4240
  • Controls Alphatronic 2000 Type PCS & LMCS (Propulsion Control System & Local Monitoring Control and Safety System)

MAN Diesel says that the complete main propulsion package concept enjoys a favourable position in a number of ship segments – amongst others for medium to large-size fishing vessels. The ‘package’ concept goes back to the original 4hp Alpha CP propeller fitted to a fishing vessel back in 1903. The company says that its L27/38-based propulsion package has proved popular for high-end Scandinavian and North Atlantic fishing vessels, with several significant references. The Frederikshavn plant continues to provide after-sales, and to assemble and test a limited number of L27/38-based propulsion packages and Alpha propellers each year, even though the foundry, engine machining and engine production facilities closed there in 2010.

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