Use of High Efficiency Propeller Designs to Optimise Propulsive

Efficiency

Adrian Miles

Managing Director Stone Marine Propulsion

Presented at ENERGY EFFICIENCY PRACTICE & PROSPECTS Athens 27/11/2012

STONE MARINE GROUP

Stone Marine Propulsion

Supply : Large Propellers & Sterngear

Stone Marine Services

Servicing : Propellers & Sterngear

Stone Marine Shipcare

Servicing : Propellers

Stone Marine Singapore

Supply : Small Propellers & Sterngear

Stone Marine Namibia

Subsidiary of Stone Marine Services

Stone Marine Bruntons

Supply : Small Propellers & Sterngear

1. The Stone Marine 'NPT' high efficiency propeller 2. Propeller Optimisation Basics. Case study 1: 'Seahorse' 35k Bulk carrier Optimise Propeller Revs 3. Slow steaming:

Case study 2: Container Vessel, De-rate Engine and fit optimised Propeller 5. Conclusions

Summary

NPT Propeller

- NPT = 'New Profile Technology'

- 2-4% Efficiency Gain

-Smaller Optimum Diameter

-Smaller Blade Surface

-Significant Weight & Inertia Reduction

-Lower Pressure Pulses

-Same Cost as Conventional Propeller

NPT Propeller – How it Works

-Reduced Pressure Peak on Section -Blade Surface Area Reduced - Viscous Drag Reduced = Improved Efficiency

Camera

Pressure

Gauge

0

1

2

3

4

5

4 8 12 16 20

Am

plit

ude[K

pa]

Order.

0.8×σdesign

MPNo.90(NBS)

MPNo.91

Measurements by HSVA(Hamburg)

Pressure Impulses Trials Powers

98.0%

99.0%

100.0%

101.0%

102.0%

103.0%

104.0%

1

Relative

Propulsive

Efficiency

Propeller

Conventional PAI NBS

Slow turning, Large Diameter = Highest Efficiency

Propeller Optimisation Basics

Maximum Continuous Rating (MCR), Power and RPM selected from 'layout' box

Engine Layout Selection

Propeller Diameter

Maximise Diameter Select RPM to Suit

Case Study 1: Seahorse 35 Bulk Carrier (Source Grontmij & Schmidt Maritime)

Case Study 1: Seahorse 35 Bulk Carrier

Case Study 1: Seahorse 35 Bulk Carrier

Version 3

Comparison between optimum diameter conventional and NPT Propellers

Case Study 1: Seahorse 35 Bulk Carrier Version 3 – Model Test

Summary of Fuel Oil Savings

Oct. 2012 14 Schmidt Maritime

SEAHORSE 35 Version 1 2 3 4 5

1. Main Engine Maker [-] MAN B&W MAN B&W MAN B&W MAN B&W MAN B&W

2. Main Egine Type [-] 5S50 5S50 5S50 5S50 5S50

3. Main Engine Mark [-] MC-C7.1 TI ME-B8.1 TII ME-B9.2 TII ME-B9.2 TII ME-B9.2 TII

4. Main Engine Tuning [-] 127rpm 110rpm 99rpm 99rpm Part Load

5. Propeller [-] 5,54 m NPT 5,80 m Wärts. 5,90 m NPT 5,90 m NPT 5,90 m NPT

6. Becker MEWIS Duct® [-] No No No Yes Yes

7. Design Speed 1) [knots] 14,0 14,0 14,0 14,0 13,0

8. SMCR2) [kW] 7.500 6.900 6.350 6.050 4.700

9. NCR3) [kW] 6.082 5.913 5.670 5.440 4.230

10. NCR verified by: [-] Sea trial Sea trial Tanktest Tanktest Tanktest

11. % of SMCR [%] 81% 86% 89% 90% 90%

12. NCR Index [-] 100% 97% 93% 89% 70%

13. SFOCNCR [g/kWh] 166,8 167,2 161,0 159,9 158,6

14. SFOC Index [%] 100% 100% 97% 96% 95%

15. M/E FOCMDO4) [mt/day] 24,3 23,7 21,9 20,9 16,1

16. FOC Index [%] 100% 97% 90% 86% 66%

1) Design speed at scantling draft of 10,1 m

2) NCR : Main engine power to reach design speed at scantling draft including 15% sea margin and 1% shaft loss

3) M/E fuel oil consumption at NCR based on MDO (LCV 42,700 kJ/kg). M/E makers SFOC tolerance of 5% is not incl.

Summary of EEDI

Oct. 2012 15 Schmidt Maritime

SEAHORSE 35 Version 1 2 3 4 5

17. EEDI1) [g/DWTxnm] 6,53 6,23 5,60 5,32 4,50

18. EEDI Index [%] 100% 95% 86% 81% 69%

19. EEDI Base Line [g/DWTxnm] 6,54 6,54 6,54 6,54 6,54

20. EEDI blw. Base Line [%] 0% 5% 14% 19% 31%

1) Main engine makers SFOC tolerance of 5% is included.

4.0

4.5

5.0

5.5

6.0

6.5

7.0

30,000 32,500 35,000 37,500 40,000

EED

I [g-

CO

2/D

WTx

nm

]

Capacity [DWT]

IMO Energy Efficiency Design Index (EEDI) - BULK CARRIERS (EEDI Base Line = 961,79 x Capacity-0,477)

Phase 0 (-0%) from 1/1 2013

Phase 1 (-10%) from 1/1 2015

Phase 2 (-20%) from 1/1 2020

Phase 3 (-30%) from 1/1 2025

Version 1

Version 2

Version 3

Version 4

Version 5

Case Study 2: De-rating Large Container Vessel

80 85 90 95 100 105

15000

20000

25000

30000

35000

40000

45000

50000

55000

60000

65000

70000

75000

Propeller Speed (rpm) v Engine Power (kW)

12 Cylinders 72240

kW

6 Cylinders

33750kW

Existing 6 Blade

Propeller

3 Blades 97 RPM

RPM

Pb

(kW

)

12 to 6 cylinders 26 to 18 kts (max) 6 to 3 blades +6.5% Propeller +6% SFOC saved Total +12% saving 2.6 years payback on $1 700 000

4000

9000

14000

19000

24000

29000

10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0

Pb

(kW

)

Vs (knots)

Containership De-rating 3 and 4 blade options

Existing Propeller 6 Blades

3 Blades NPT

4 Blade NPT

Case Study 3: De-rating Large Container Vessel

Over 75 NPT Propellers on order or supplied

Over 100 of predecessor 'NBS' types in Japan

Largest NPT to date 10.4m, 67t mass

NPT Propellers Supplied

Conclusions Large diameter, slow turning best for efficiency Newbuilds should use this principle to set MCR Retrofits can use this principle to de-rate engine NPT Propeller smaller diameter = lower rpm = higher efficiency