Improving fuel efficiency

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Improving fuel efficiency


The price of fuel can have a dramatic effect on the marine industry’s commercial profitability, this guide gives a brief overview of the key areas where significant cost reductions or improvements can be made.

Economic benchmarking

Benchmarking is a way to compare the financial performance of a vessel to the best-in-class. It compares operational processes, financial performance and other measures of the efficiency of a vessel’s activities. You can compare results against other vessels in the same segment or against your vessel’s previous performance to identify potential improvements.

Vessel optimisation and propulsion

Another significant factor affecting fuel efficiency is vessel design and the correct matching of the propulsion system (engine/gearbox/propeller) for the task in hand.

  • The ratio of a vessel’s length to beam can have an effect on fuel efficiency – ratios of 3:1 and 4:1 can be beneficial
  • Using the correct engine for the vessel is imperative
  • Assess the gearbox. As well as heat loss, friction increases running costs


Vessel and hull maintenance

A dirty hull is like driving a car with the handbrake on. Poorly finished paintwork can have a similar effect.

An often overlooked area of potential fuel savings is vessel and hull maintenance. Little financial outlay is required but the benefits can be worth it over time.

  • Excess paint can add to vessel drag
  • The correct type of antifouling paint is important – some antifouling paint contains solvents which actually feed marine growth. Consider using solvent free (ceramic type) paint

Operational husbandry and auxiliary engines

Fuel flow metres can help you save around 10% on your fuel bill. If you can’t measure it, you can’t save it.

‘Good housekeeping’ on-board a vessel and operational fuel-saving practices, such as using a fuel flow meter, should not be underestimated.

  • Steaming speed should be considered: engines are usually at their most efficient at 80% revs – burn 70% of fuel and achieve 90% of the speed compared to full throttle
  • Keeping a true course can save fuel – it may seem obvious but planning the shortest journey to take account of tide, weather and wind can make a difference
  • Hydraulics should be switched off or declutched when not in use

New vessel design and new builds

Hydrodynamic bow designs reduce the resistance through the water.

  • Using a fixed nozzle in your propulsion system – up to 33% fuel saving is possible with 7.5% increased thrust
  • Catamaran design – a 2:1 length beam ratio is possible without detriment to fuel efficiency dependant on hull form (when compared to mono-hulls)

Engine maintenance and monitoring

Poor combustion chamber sealing can lead to high fuel consumption. Regular maintenance is crucial to reducing fuel consumption.

  • Monitoring air intake is important and could save up to 20% on the fuel bill. A hard to open door/hatch indicates a vacuum in the engine room
  • Return fuel lines should be checked. In some engines, 90% of the fuel delivered by the pump is returned to the tank via the return fuel line.
  • Fuel injectors should also be monitored. Spray pattern is critical for engine efficiency, fuel economy and exhaust emissions
  • Exhaust smoke should be checked. Black exhaust smoke could mean an overloaded engine, shortage of air or faulty injectors. White exhaust smoke could mean injectors or valve timing is out, or that leaking valves, damaged or worn piston rings are causing low compression. Blue exhaust smoke could signal burning lube oil, due to worn valve guides or a worn or broken piston

Fuel husbandry

Rather than treat contamination when significant operational or fuel quality problems arise it is better to prevent microbial growth occurring. Much can be done to ameliorate problems associated with microbial contamination in fuels, these include:

  • Allowing fuel deliveries to settle in the tank for 24 hours before putting the tank back into service
  • Drain any accumulated water from the bottom of the tank weekly
  • Routinely test bottom samples for microbial contamination
  • Treat fuel if required, according to test results

“Since the introduction of Bio Diesel, diesel fuel carries less sulphur and more water due to the manufacturing process, meaning from the pump there is more water in fuel at source. The advice to combat this would be to not store large amounts, but instead burn through it and turn it over regularly.”

This changes the theory of fuel management on boats, but in practice many owners have not adopted this. Hence fuel bug is becoming an epidemic and most boats storing fuel for periods longer than 3 months, especially in warm environments will have fuel bug to some degree or another. Not a problem in the early stages as the fuel filters cope with this, but when there is significant amounts, the filters soon become blocked, starving the engine of fuel and eventually cutting it out, or worse causing pump or injector damage.

With this being the case, installing an MLS fuel purifier would be the best solution. They come with a 5 year warranty and are guaranteed to remove 99.9% of all water and 98.7% of all other contaminants, including fuel bug”
Ben Metcalfe, Chief Executive, Landau UK

MLS Fuel Purification

Originally tested in the haulage and plant industry and now well received into the marine industry since 2013 by commercial boat builders, the MLS Fuel Purifier is designed to remove both water and solid particulates from even the dirtiest, most contaminated fuel, prolonging an engine’s life.
Engine benefits:

  • Avoid fuel/water related breakdowns
  • Maintain exhaust emission standards
  • Extend engine rebuild and life
  • Remove solid/semi solid contaminants such as dirt, rust and sludge

Major environmental benefits:

  • Cleaner engine combustion
  •  Save on paper consumables as the Fuel Purifier is filter-less
  • Significantly extend the life of the standard fuel filter
  • Fewer unscheduled repairs and calls outs. Installed between the fuel tank and the primary fuel filter/water separator, the MLS Fuel Purifier acts as the first line of defence by removing water, dirt, sludge and grit

Landau UK are supplying the MLS fuel purifier to a number of commercial vessels from military and defence fleets to private individuals and the market is growing exponentially


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01489 577 588

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