Clean Water - Fuel Efficiency and Alternative Fuels

Fuel Efficiency
With ever rising fuel prices and concerns over fuel supplies, boaters are paying attention to the efficiency of their engines now more than ever. Increasing your fuel efficiency saves you time with fewer trips to the fuel dock; saves money through using less fuel; and saves the environment with decreased emissions. Here are a few tips to help you get the most out of your tank of fuel:

  • Tune your engine and keep the boat bottom clean & barnacle free. A properly tuned engine not only gets better mileage, it just runs better and has fewer emissions. A fouled bottom also has more drag, making your boat work harder than it needs to.
  • Use the appropriate propeller and check for damage. Using the stock propeller may not be best suited for your type of boating. By experimenting with different props, you may find one that saves fuel and improves performance. Also, a damaged prop, even a slight "ding," can negatively affect fuel efficiency and performance – get it fixed!
  • Drain boat of all unnecessary water before leaving the dock At about eight pounds a gallon, excess water weight can really add up. The lighter your boat is the better gas mileage you'll get. Keep bilges dry and top off water tanks only if you'll think need it.
  • Reduce unnecessary weight and wind resistance. Bring only the gear you'll need for your outing. Leave long range cruising gear at home if you are only headed out for the day. Clear your decks of clutter and lower canvas tops, they create drag.
  • Balance your load and allow the boat to plane quickly. Many boats are stern heavy with occupants, motor, batteries and fuel. Consider moving passengers forward when accelerating or moving some of your heavier items forward to balance your load.
  • Throttle back to cruising speed or sweet spot. Chances are that your boat does not get the best mileage at full speed. Once you get up on a plane, throttle back slightly or find that "sweet spot" where your boat rides smooth and level and performs its best.
  • Avoid excess engine idling. Even when idling in neutral, your boat is consuming fuel and the noise can be especially annoying to those around you. Plus idling can produce potentially deadly carbon monoxide (CO) fumes.
  • Use the proper fuel to oil mix for your engine. If you must mix your own fuel, follow the manufacturer's recommendations. Too little or too much oil can harm your engine, affect overall performance and reduce fuel efficiency.
  • On larger boats, install a fuel flow meter. In addition to showing gallons used and gallons remaining, these new devices also allow you to see real-time fuel efficiency in gallons per hour. A fuel meter can also help you find the ideal settings for maximum efficiency and performance.
  • Purchase a low emission, fuel efficient engine. When looking at a new boat or repowering your existing one, look for an engine that promises better fuel economy and lower emissions. Today's engines even rival the raw power of older gas-guzzling engines.
Alternative Fuels
The BoatU.S. Foundation worked with the Maryland Soybean Board to evaluate the use of a vegetable based diesel fuel, called biodiesel, as an alternate fuel source in marine engines. Tested previously in city buses in Philadelphia, Washington, and Baltimore as a way to help improve urban air quality, efforts are increasing to bring this product to the mainstream marine market.

After a review of existing research, the Foundation determined that using biodiesel at a 20% blend with 80% petroleum diesel will:

  • Reduce unpleasant exhaust odors.
  • Improve lubricity.
  • Help clean injectors, fuel lines, pumps, and tanks.
  • Improve diesel engine performance.

However, there are some side effects to using this product. For example, as it helps clean out fuel lines, fuel filters will need to be replaced at closer intervals. In addition, both the higher cost per gallon and the ability for the average boater to obtain the product are hindrances to immediate widespread acceptance. Want to know more? See our Biodiesel Frequently Asked Questions.


Logo of the, "help stop the drops" clean water initiative