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
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