1. Home
2. Environment
3. Environmental Programs
4. ecoTRANSPORT
5. ecoFREIGHT
6. Marine
7. Best Practices for Marine Vessels

Best Practices for Marine Vessels

The analysis and conclusions contained in this case study are those of the authors alone and do not necessarily represent the point of view of the Government of Canada.

Organization
Innovation Maritime

Major Finding
Detailed analysis of basic operational procedures using accurate performance measurement systems can result in fuel efficiency gains and lower greenhouse gas emissions on a merchant vessel.

Project Timeline
November 2006 to March 2007

Please note that some figures such as cost savings on fuel are based on data from the period that this project took place.

Introduction

Increasing public awareness of carbon fuel emissions and rising fuel prices demand increased efforts to maximize transportation efficiency. While marine transportation is already a very efficient mode of freight transportation in terms of fuel consumption and greenhouse gas (GHG) emissions, one of the simplest ways of improving marine vessel performance is to use maintenance and operational best practices.

Project Description

Innovation Maritime arranged with the Société des traversiers du Québec to undertake performance assessments of the vessel Camille Marcoux (Figure 1), a ship that carries freight and passengers between the South and North shores on the St. Lawrence River in Eastern Québec year-round.

The Camille Marcoux is a RoRo (roll on, roll off) ferry with a dead weight of 6,122 tonnes and a maximum cruising speed of 16 knots. Its four engines each generate 1,790 kW at 750 rpm.

Based on consultations with company managers and marine engineers, the following areas of performance improvement became the project focus:

• Engine overhaul and adjustments
• Engine configuration optimization
• Autopilot optimization
• Crew training on the use of performance indication instruments

Project Goals and Objectives

The objective of this project was to demonstrate the benefits of improved practices for merchant ship operation. Best practices include:

• Reduce fuel consumption and GHG emissions from the main propulsion engines.
• Use performance indicators to increasing the vessel's overall efficiency.
• Develop ship management practices.
• Educate and motivate the crew to minimize fuel consumption/GHG emissions

Project Methodology

Meetings held with company representatives and crewmembers helped define the four potential areas of improvement. The ship was inspected to confirm it was suitable for the study and to determine any instrument requirements.

Measurement equipment that was installed included:

• Enclosures and cable connections in the shaft room, engine control room and wheelhouse;
• Torque meters on the two intermediate propulsion shafts, modifications to the fuel supply piping;
• Flowmeters and RPM sensors for the four main propulsion engines; and
• Data display and acquisition system, fuel flowmeter computer and ship-to-shore data communications equipment.

A portable gas analyzer continuously measured the four main engines for exhaust gases. Fuel use baseline data was obtained from company records and from the engine manufacturer. A computer-based acquisition system was installed on the ship to centralize information logging from the ship's continuous monitoring equipment.

Data was collected to monitor greenhouse gas emissions, specific fuel consumption, average fuel consumption per nautical mile, engine parameters, ship speed versus fuel consumption and ship speed versus freight load.

Finally, a permanent computer-based system was installed to provide crew with constant data about the ship's fuel consumption/greenhouse gas emission performance.

Results

Engine overhaul adjustments: As an engine's running hours add up, fuel efficiency goes down and GHG emissions rise. In the case of the Camille Marcoux, one engine is overhauled per year - after about 15,000 working hours. Due to the short duration of the study, it was not possible to compare the performance of a newly overhauled engine to one that was approaching overhaul. Instead, Engine 1 (1,000 hours) was compared with Engine 4 (7,500 hours) using continuous measurement equipment. Table 1 shows that Engine 4 produced 3.4% less power than Engine 1 and used 3.9% more fuel per kilowatt-hour. It would be expected that the difference in performance would be greater if the difference between running hours were greater.

          Table 1 Engine performance comparison

	Engine 1	Engine 4	Variation (Engine 4 to Engine 1)
Hours	1,000	7,500
Power output (kW)	1,423.1	1,374.1	-3.4%
Fuel consumption (L/hr)	401.9	402.3	+0.1%
Specific fuel consumption (L/kWh)	0.282	0.293	+3.9%

Partial engine overhauls are usually done when a ship is in port, which can result in less-than-ideal fuel usage if cylinders are maladjusted and unbalanced. There are two options for maximizing propulsion engine performance. For ships that do not operate in winter, the overhaul of engines could take place at this time. In the case of ships like the Camille Marcoux that operate year-round, it is possible to operate on three engines while the fourth engine is undergoing overhaul while the ship is in service. Engine overhaul timing needs to consider the cost of additional fuel usage versus the cost of overhaul.

Engine configuration optimization: The Camille Marcoux has four engines powering two shafts. One or both engines can power either shaft. Testing compared combinations of engines as follows:

• Configuration A: Two engines running - one per shaft
• Configuration B: three engines running - one powering the starboard shaft and two powering the port shaft
• Configuration C: Four engines running - two per shaft

For a given Matane to Baie-Comeau crossing, Configuration A did not generate enough speed for the ship to meet its schedule. Configuration B allowed the ship to just meet the crossing schedule. This is the engine configuration most often used and results in a fuel consumption of 2,632 L per crossing. This configuration requires the automatic pilot to apply the rudder - up to 15° - to compensate for unequal power between the two shafts. The rudder drag raises fuel consumption.

Calculations showed that the most fuel-efficient operation occurs when Configuration A (two engines running) occurs for 1.02 hours of the crossing and Configuration C (four engines running) occurs for the other 0.96 hours. This combination saves 147 L or 5.5% per crossing. This analysis shows that careful examination of propulsion schemes can result in significant fuel and GHG emission reductions.

Autopilot optimization: Records of the ship heading variations were made for engine Configurations A (two engines) and B (three engines). Configuration B results in continual steerage adjustments of the rudder from 0 to 15° and results in variable engine power and fuel waste.

The Camille Marcoux's autopilot system is a fully analog type typical of ships built in 1973. For best autopilot operation, several adjustments need to be made. During the study, variable wind, wave and current conditions made it impossible to make all the necessary adjustments. However, some adjustments that were made reduced rudder use and saved fuel. This aspect of the study demonstrated the importance of autopilot calibration for fuel economy. It also invites a cost-benefit analysis to predict the likely financial advantage of replacing the analog autopilot with a modern unit.

Performance indication instruments and crew awareness: This study called for instruments to be installed in the wheelhouse that provided the crew with vital performance indicators such as continual information about fuel consumption and emissions. Although the instruments were not in place long enough during the study to measure changes, installations on other vessels have increased efficiency by 3 to 10%

Conclusion

This project demonstrated that detailed analysis of basic operational procedures using accurate measurement equipment increases a merchant vessel's fuel efficiency and reduces its GHG emissions.

The best practices for the Camille Marcoux allow management and crew to make decisions about maintenance and operations based on verifiable data that will lower fuel consumption and GHG emissions. The lessons from this demonstration project can be applied to other Canadian vessels.

Additional Information

• Société des traversiers du Québec
• Innovation Maritime
• OpDAQ Systems

Alternative Format

The following document is available for downloading or viewing:

PDF version (Size: 160 KB)

Date modified:

2012-03-14

Primary navigation