DYNAMIC POSITIONING CONFERENCEOctober 14-15, 2014

THRUSTERS

Unsurpassed Efficiency, Dual-End CRP Technology

Return to Session Menu

Kari KyyröSteerprop

A i thi U it T / StAzimuthing Unit Types / Steerprop

213.11.2014

Azimuthing UnitsAzimuthing Units with Contra-Rotating Propellers (CRP)

Combining DP-Capability with Outstanding Fuel Economy

313.11.2014

D l E d CRP P lDual-End CRP PropulsorBASIC PRINCIPLES

• Mechanical power transmission• Fixed pitch propellers• Dual-End CRP configuration• Simple construction• Torque sharing• Available up to 20...25 MW

Efficiency and rugged mechanical reliability

413.11.2014

Torque SharingTorque Sharing

Slow, large propellers

Two gear contacts share the torque

513.11.2014

Increased Propeller AreaIncreased Propeller AreaIncreased Propeller AreaIncreased Propeller Area

613.11.2014

Forwardpropeller

Aftpropeller

Energy RetrievalEnergy Retrieval

Retrieval of rotational energyCRP

713.11.2014

Body InteractionBody Interaction

Favourable Favourable gear pod ↔ propeller gear pod ↔ propeller interactioninteractioninteraction interaction counteracts gear pod counteracts gear pod resistanceresistance

BodyBodywakewake

BodyBodywakewake Large gear & high Large gear & high

torque capacitytorque capacitywithout sacrificingwithout sacrificing

ffffefficiencyefficiency

813.11.2014

Dual-End CRP PropulsorDual End CRP PropulsorHYDRODYNAMIC PERFORMANCE

1. Large slower propellers • torque sharing

2. Increased propeller disc area 3. Retrieval of rotational energy

• CRP concept

4. Pulling front propeller • Undisturbed inflow for little• Undisturbed inflow for little

cavitation and low excitations

5. Beneficial propeller ↔ body hydrodynamic interaction

High efficiency High efficiency -- Low pressure pulsesLow pressure pulses

913.11.2014

Dual-End CRP Azimuth Propulsion

vs.Other PropulsorOther Propulsor Configurationsg

1013.11.2014

1113.11.2014

1213.11.2014

Case Study: High Speed PSV

Operational profile:• 14 hours loading at docksideg• 16 hours discharging on DP• Sailing in and out, 15 knots• Power 2 x 2460 kW diesel-electric• Service speed 15 knots at 90% MCR• DP at 15% average power

1313.11.2014

Case Study: Propulsor Configurations

Open NSMB 19A Steerprop HJ3Opepropeller

NSMB 19A Nozzle

Steerprop HJ3 High Efficiency

Nozzle Dual-End CRP

1413.11.2014

Case StudyPSV, 2x2460 kW, 15 knots @ 90%, DP @ 15% power

10%

ons

ley

0%

5%

emis

sio

ard

nozz

l

19A-nozzle

-10%

-5%

mpt

ion

&

o st

and a

-20%

-15%

con

sum

mpa

red

t

HJ3-nozzle

-25%50 70 90 110 130 150 170 190

Sailing distance / nm

Fuel

com CRP

1513.11.2014

Fixed vs. Controllable Pitch

Th t d i ffi i• Thrust producing efficiency: – FPP: ~same thrust per power^(2/3) independently of loading – CPP: low thrust per power^(2/3) at low loading (high rpm)

• Vibration and noise: – FPP: low rpm → low excitations at low loading – CPP: high rpm → high excitations at low loading possible

• Mechanical robustness & reliability FPP: simple construction– FPP: simple construction

– CPP: complex mechanism

1613.11.2014

Fixed vs. Controllable Pitch (continued...)

P il bilit• Power availability: – FPP: some max. power restrictions in bollard and/or free sailing

o field weakening & well-selected design point → restrictions small – CPP: max. power available in both bollard and free sailing

• Reverse thrust by changing propeller rotation direction FPP: typically ~20% of max forward thrust available– FPP: typically ~20% of max. forward thrust available

o gear restrictions – CPP: typically ~55% of max. forward thrust available

1713.11.2014

Dual-End CRP Azimuth Propulsion

in Icein Ice

1813.11.2014

Testing at Aker Arctic

1913.11.2014

Testing at Aker Arctic (continued...)

2013.11.2014

Dual-End CRP in Ice

Hi h th t• High thrust

• Propellers far from each other No ice floes with simultaneous contact to both propellers– No ice floes with simultaneous contact to both propellers

• Concentrated wake– Excellent ice managementExcellent ice management – Flushing of the hull to reduce ice friction

2113.11.2014

Dual-End CRP in Ice (continued...)

2213.11.2014

ConclusionsConclusions• Ducted propulsors provide the highest bollard pull, but fuel p p p g p ,

economy isn’t so good for a typical operating profile

• Diesel-electric machinery with FPP propulsors provides a d ll f l ffi igood overall fuel efficiency

• Dual-End CRP provides the best fuel efficiency and also a high bollard pull g p

• Mechanically simpler FPP provides more rugged reliability than complicated CPP systems

• Dual-End CRP has excellent ice management properties

2313.11.2014

Steerprop Ltd

P O Box 217

Steerprop Ltd.

P.O. Box 217FIN-26101 RAUMAFinland

Phone +358 2 8387 7900Fax +358 2 8387 7910Fax +358 2 8387 7910E-mail steerprop@steerprop.com

www.steerprop.com