Hush! Hush! Seismic Vessel Package Contract for MAN Diesel & Turbo

By George Backwell at June 29, 2013 01:06
Filed Under: General

Cavitation noise reduction –  underwater noise has a deleterious effect on sensitive seismic data streams – was the target for MAN Diesel & Turbo designers when they set about the task of creating a power and propulsion package for a new GC Reiber Shipping seismic survey vessel. This object they ingeniously achieved and were rewarded with a contract (option for a second vessel) to supply four MAN 8L32/44CR B.2 engines to power proprietary propulsion machinery.

The vessel design is an ST 324 XT from Skipsteknisk of Aalesund, Norway whose hull will be constructed in Poland with outfitting subsequently to be carried out at the Myklebust shipyard north of Aalesund. The propulsion plant is scheduled for delivery by May 2014 with vessel delivery following in March 2015.

Graphical rendering of the new seismic vessel: Image courtesy Skipsteknisk

Power and gearing arrangements
Four of the 4-stroke 8L32/44CR B.2 common-rail engines (delivering 600 kW/cylinder) along with 2 × 2-speed Flender Twin-In/Single-Out reduction gears and MAN Alpha Twin Screw CP propellers in AHT nozzles, will power the vessel.

The reduction gears from Siemens-Flender are specially designed such that – at constant engine speed (750 rpm) – two different propeller speeds can be selected (155 rpm or 120 rpm), allowing the propellers to have a much wider silent-operation window. The TI/SO gears are also provided with 2 × 2,600 kWe PTOs each.

A 4-stroke 8L32/44CR B.2 common-rail engine: Photo courtesy of MAN Diesel & Turbo

Expertise in ice has long been a GC Rieber Shipping trademark with an emphasis on delivering customer solutions for demanding operations in sensitive environments where quality, safety and environmental concerns are crucial. Thus a special feature of the design for the vessel which is to be annotated DNV Ice 1A* is an ‘ice operation mode’ so as to comply with class rules that require one engine (and not two) to be attached to each twin propeller shaft when operating in ice conditions.

Propulsion package
The MAN Alpha VBS1100 Mk5 CP propellers utilise, courtesy of up to six operating modes, the flexible propeller-output speed to operate at the optimum efficiency in all modes in order to help suppress cavitation on the pressure side.

The ø4200 CP propellers operate in Alpha High Thrust (AHT) nozzles, which further help to increase propeller performance by offering higher thrust at low vessel speed, and reduce cavitation noise through selection of the optimum nozzle L/D ratio.

The Alphatronic 2000 remote-control system facilitates the most favourable propulsion-plant control in all operating modes.

Finally, as part of the overall deal, MAN Diesel & Turbo will provide two years of online service and PrimeServLab (stringent quality control for engine operating fluids) in order to obtain valuable performance data for seismic high-load operation.



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