Anyone who uses motorized engines to power their boats is familiar with boat fuel. Boat fuel is made of either gasoline or diesel fuel which is sometimes mixed with fuel stabilizers. If you are going to use boat fuel to power your engine and you want to know more about it, we have assembled some useful information here.

Boat Fuel Facts of Interest

pump used to fuel the tanks of visiting boats.

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Boat fuel powers different boats in different rates and at different speeds. For example, a 33-foot sailboat with a 25-horsepower engine can travel for 300 miles at 7 knots on about 50 gallons of diesel fuel. The same 50 gallons of diesel fuel would also power a 40-foot Sportfisher boat for 33 miles at 40 knots of speed. The faster you go the more fuel you will use, exponentially, in most boating situations.

New, Gasoline

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Boat fuel Is consumed in a variety of different ways. Here is a breakdown of the percentages of how your fuel is used when you operate your boat:

  • 1% of your fuel overcomes air resistance
  • 2% is used up with friction at the propeller shaft
  • 6% is used up to overcome prop-wash and wave formation against the hull
  • 7% is used to overcome skin friction
  • 10% of your fuel overcomes wave force resistance
  • 25% of your fuel is wasted on heat and vibration with the surrounding water
  • 35% of your fuel disappears into the atmosphere in heat form
  • Only 13 to 14% of the energy from the fuel actually powers the propeller on your boat

Diesel and gasoline are different in several ways, but they are the most common fuels used for boats. Diesel fuel engines on average consume one gallon of fuel for every 18-horsepower generated. Four-stroke gasoline engines on the other hand use up about one gallon of fuel for every 10-horsepower provided to your boat.

The rule of thumb when you are using any boat fuel is to plan your trip by using 1/3 the fuel that you have to get to your destination and 1/3 of your fuel to get back, leaving 1/3 of your fuel for emergency use.  Any use of fuel to gain excess speed is a waste of fuel for unnecessary speed in most cases.


Should I add fuel stabilizer?

Boat fuel stabilizer

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Fuel stabilizer is an additive added to gasoline or diesel fuel that prevents the breakdown of the fuel.  There is a number of factors that will create fuel breakdown, including oxidation of the fuel based on oxygen reacting with a fuel over time, and the absorption of water from the surrounding environment.  Some gasoline is actually ethanol which will attract and absorb water at a much higher rate than regular gasoline.

Fuel stabilizer is the recommended fuel additive for most marine applications, as water makes its way into the fuel one way or another usually to some degree.  Fuel stabilizer eliminates the water that gets into the fuel and prevents fuel breakdown in the process. It is highly recommended that if you are going to store your boat or marine fuel for any length of time that you add fuel stabilizer to it to prevent fuel breakdown.


All about Marine Gas and Fuel Tanks

No matter what the name you use for them, boat gas tank, boat fuel tank, or marine fuel tank, these tanks are the devices that store boat fuel for use in boats.  Here is a breakdown of some of their features here:


Plastic marine fuel tanks:

Marine Portable Fuel Tank - 6 Gallon Capacity

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  • The polyethylene construction is highly resistant to corrosion and is virtually waterproof
  • These tanks are known to outlast aluminum marine fuel tanks most of the time
  • Usually, the cost for less than aluminum marine fuel tanks on average
  • Recently designed polyethylene tanks are compatible with ethanol


 Aluminum marine fuel tanks:

A baffled ski boat fuel tank

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  • Aluminum tanks that are correctly mounted should outlast the boat in most situations
  • Aluminum tanks mostly have baffles within them to prevent swashing of fuel
  • These tanks are stronger and are more resistant to punctures than plastic tanks

Marine fuel tanks are installed directly into the boat but some of them are actually portable and can be transported to and from your boat easily.  Most plastic marine fuel tanks are portable although most aluminum marine fuel tanks are installed directly into the boat.


A Few Tips for Using Boat Fuel to Remember

Plastic Marine Fuel Tanks

Photo credit to Tropical Boating

Always practice safe boating practices no matter what you do.  Always check fuel lines and boat fuel tanks for any holes or punctures. One of the best ways to check for fuel leaks in to smell around the areas of the engine and fuel tanks.

If you smell any fuel do not start your engine and diagnose the problem and never operate your system if there is a doubt of a fuel leak.  Many tragedies have occurred because of improper safety practices being observed but these can easily be avoided with a routine check of boat equipment and systems.

Feature image via Boating World