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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 [email protected]
www.steerprop.com