Reducing Ship Emissions: a review of potential
practical improvements in the propulsive efficiency
of future ships
Prof. I Ketut Aria Pria Utama, FRINA
KIR-AIPI / ITS

BACKGROUND
• Environmental issues such as the emission of greenhouse gases, pollution,
wash and noise are having an increasing impact on the design and
operation of ships.
• These environmental issues together with economic factors, such as rising
fuel costs, all ultimately lead to the need to minimise ship propulsive
power.
• Various methods and devices for reducing propulsive power are reviewed
and discussed. The most favourable methods, from a feasible and
practical point of view, are identified and quantified.
• It is found that potential reductions in the resistance of existing good hull
forms are relatively small, but optimising hull-propeller-rudder interaction
offers very promising prospects for improvement.
• The biggest potential savings in power arise from optimised operational
strategies such as the use of optimum trim, speed and weather routeing.

CONTENTS
• Introduction
• Quantifying the Environmental Impact of Ship Propulsion
• Powering
• Power Savings during Design
• Power Savings during Operation
• Auxiliary Propulsion Device
• Economic and Environmental Issues
• Design Procedures
• Conclusions

POWERING
• Overall Concept
• Components of Powering
• Reduction in Propulsive Power
REDUCE VESSEL RESISTANCE Hull shape, surface finish
Appendages: low drag design
Superstructure (air drag): low drag design
IMPROVE EFFICIENCY OF PROPULSORS Choice of design parameters, surface finish
Adaptation to actual hull wake
OPTIMISE HULL/PROPELLER/RUDDER
INTERACTION
Optimise wake distribution
Minimise thrust deduction
Upstream flow conditioning
Recovery of rotational energy
OPTIMISE STRATEGY FOR OPERATIONAL Speed, including slow steaming
Trim: monitor/optimise
Weather routeing
Hull/propeller cleaning
TransmissionT R
Fuel V
Propulsor efficiency
PD
PS
efficiency
Main
engine
efficiency
Hull resistancePropeller
thrust

POWER SAVINGS DURING DESIGN
• Hull Form
• Hull Surface Finish
• Appendages
• Air Drag
• Propulsive Efficiency
• Propeller Hull Interaction
• Propulsion Machinery and Fuels

POWER SAVINGS DURING OPERATION
• Speed
• Effect of Trim on Hull Resistance
• Weather Routeing
• Hull Propeller Cleaning

AUXILIARY PROPULSIVE DEVICES
• Propulsive power using renewable energy: wind, wave, solar
power.
• Wind turbines and solar panels, may be used to provide
supplementary power to the auxiliary generators.

ECONOMIC AND ENVIRONMENTAL ISSUES
11.0
11.5
12.0
12.5
13.0
13.5
14.0
EEDI(CO2index)
EEDI CO2 Index
24.5
25.0
25.5
26.0
26.5
Requiredfreightrate
RFR (fuel cost $300/tonne)
5.0
5.5
6.0
6.5
Annualcapitalcharges($m)
Annual capital charges
1.5
2.0
2.5
3.0
5.0 5.5 6.0 6.5 7.0 7.5 8.0
L/B
Annualfuelcharges($m)
Annual fuel ($300/tonne)
Influence of L/B on CO2 index
Influence of L/B on Annual Capital Charges
Influence of L/B on Required Freigh Rate
Influence of L/B on Annual Fuel

DESIGN PROCEDURES
OPERATING ENVIRONMENT AND
OWNERS REQUIREMENTS
Deadweight, speed, range
FEASIBLE TECHNICAL DESIGNS
Principal dimensions, masses/capacity, power
ESTIMATES OF BUILDING and
OPERATING COSTS and REVENUE
ECONOMIC EVALUATION OF
ALTERNATIVES
CHOICE
DETAILED DESIGN
CONSTRUCTION
OPERATING ENVIRONMENT AND
OWNERS REQUIREMENTS
Deadweight, speed, range
FEASIBLE TECHNICAL DESIGNS
Principal dimensions, masses/capacity, power
ESTIMATES OF BUILDING COSTS,
OPERATING COSTS, REVENUE and
EMISSIONS
ECONOMIC
EVALUATION OF
ALTERNATIVES
CHOICE
DETAILED DESIGN
CONSTRUCTION
ENVIRONMENTAL
EVALUATION OF
ALTERNATIVES
WEIGHTED EVALUATION
Overall design flow path Overall design flow path incorporating
environmental effects

CONCLUSIONS
• General
• Resistance
• Propeller Efficiency
• Hull-Propeller-Rudder Interaction
• Operation
• Savings
• Economic Viability
• Design Procedures