Learn About Marine Fuel Types & Additives

Posted by MarineFuel News
August 3rd, 2009
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As with automobile and aircraft fuels, marine fuel is available in several different types, grades, and brands. Engine type, expense, origin, and other factors may be considered when selecting marine fuels. Using the right fuel additives is also important to successful boating.


Choosing the right marine fuel can improve your engine’s performance, efficiency, and reliability. Specific fuels produce better results in one kind of marine engine than another. Large commercial ships, small recreational boats, and ocean vessels typically use different varieties of fuel. The availability of various fuel types can depend upon trucking, farming, and heating fuel demands in a particular region.


Multiple grades of a marine fuel might be available at a marina or port, especially for non-recreational boats. Two of the most common grades are called DMA and DMC. Others include DMB, DMX, and IFO-180. People may sometimes refer to these grades by various other names; ask for clarification if necessary.

Grades reflect different levels of ash, sulphur, and viscosity, among other characteristics. It’s better for engines and the environment when fuels don’t have an excessive sulphur level. The ash level indicates metal contents, which may or may not be an integral part of the fuel. The right viscosity level depends upon the specific type of engine. Consult your owner’s manual and/or marina staff for help selecting a fuel or grade.

DMB grade fuels are frequently used to power sizable ocean vessels, while smaller commercial ships like ferries and tugboats generally run on DMA. Some mariners employ DMX fuels for emergency purposes during cold weather. DMX is purchased in relatively small quantities and it should be kept in drums.

It is wise not to mix two or more grades/types of fuels in the same vessel; this can harm engines. If there is no other choice, try to add a marine fuel that is similar (density and viscosity are the most relevant factors) and/or use up as much as possible of the existing fuel before purchasing more. Mixing ought to be avoided in storage as well.


Numerous watercraft (motorboat, jet ski, PWC) run on gasoline and are often used for recreational purposes. Although such fuels are available at both marinas and automotive gas stations, care should be taken to obtain the right type. Grades of gasoline aren’t particularly consequential, with a few exceptions. Boaters may use reformulated gas, but it becomes more important to have regular tune-ups and prevent water from getting in the fuel.

It is best to avoid using gasoline which contains ethanol. Where this is not possible, various precautions should be observed to prevent damage and maintain good performance. In no circumstance should gasoline blends containing more than ten percent ethanol be used (E15, E20, E25, etc) be used in marine applications.  E10 and blends under 10% can still cause damage or other problems, especially in older boats. Unfortunately, more and more gas suppliers have been adding ethanol to their gasoline.

compare marina gas pricesOBTAINING FUELS

There are many different ways for mariners to receive fuels they have purchased. Marine fuel is often supplied to large ships via pipelines, barges, or other boats. Gasoline may be collected in gas cans, filled at a gas station while the boat is on a trailer, or obtained from a pump at the marina’s dock. It is less costly at gas stations, although not as convenient. 

Find Ethanol-Free marinas in the United States, Bahamas and Caribbean, click here.


Boaters can take steps to use less fuel, thus saving money, reducing their environmental impact, and promoting clean water. Several of these measures resemble techniques used to decrease automobile fuel consumption; don’t leave the engine idling too long, avoid high speeds, and be careful not to spill fuels. Using sailboats or canoes with outboard engines (rather than completely motorized boats) is another way to conserve fuel. Some marine fuel additives can help enhance efficiency as well, such as Chevron Marine Combustion Improver.

BRAND NAMES (NOT specially formulated for marine applications)

Boat owners may also want to take the brands of different fuels into consideration for various reasons. Such concerns might be applied to fuel for automobiles, gasoline-powered boats, and other vehicles as well. Here is a brief overview of each major marine fuel supplier’s location, brand names, and fuel sources:

California-based Chevron derives its petroleum from several different regions, including Central and Southeast Asia, Latin America, the Arabian Peninsula, Europe, Africa, and N. America. It operates in countries such as Canada, the U.K., Kazakhstan, and Nigeria – where rebels have targeted it with attacks and kidnappings. The Chevron Marine Products, LLC division sells its marine fuels in the U.S.

BP has production operations in many nations spanning all six continents. They include Angola, Indonesia, Kuwait, Canada, Norway, Azerbaijan, Kazakhstan, Colombia, and the United States, among others. The company’s products are available throughout much of the world. It is based in London and also operates the Castrol brand name. BP Marine offers a variety of fuels in numerous countries.

Shell, which is headquartered in Holland, operates throughout three different continents. It has production projects in the Gulf of Mexico, Qatar, Brazil, and Malaysia. The company also has part ownership of facilities in Canada and the U.S. It sells maritime supplies through the Shell Marine Products division. As of 1999, Shell’s IFO-180 grade marine fuel had slightly lower ash and sulfur content than Mobil’s, and its DMC and RMH-45 fuels had a lower ash volume.

A merger created the major U.S. oil company ExxonMobil about ten years ago. It operates in Russia, Qatar, Angola, Nigeria, Cameroon, and other countries. Some of its activities in Central Africa and the southeast Asian nation of Indonesia have come under criticism by human rights organizations. The Esso brand (which appears to be more common outside of the U.S.) is part of ExxonMobil Corporation as well.

A smaller company, Irving Oil supplies residual and marine gasoil fuels in east Canada and the northeastern United States. It is headquartered in Saint John, Canada with its U.S. division based in New Hampshire. The company refines and delivers its petroleum from a refinery in New Brunswick. It also runs a major gas station chain throughout the same region.

Marathon Oil operates in a few relatively stable African countries, including Gabon, Angola, and Equatorial Guinea. Some of its fuels also come from Norway, the Gulf of Mexico, Indonesia, the U.S., and the United Kingdom. Primarily, its operations are in the West African and North American regions. Marathon is based in the city of Houston, Texas.


In addition to these fuels, various fuel additives are available for marine purposes. Such products can offer operational, economic, and environmental benefits. Fuel stabilizer additives are useful when storing a boat during the winter or other months it isn’t used. Lead substitutes will often provide benefits for an old engine. A condensation absorbing additive can prevent corrosion and improve engine performance.  Keep in mind that some additives are available in separate diesel and gasoline versions.

ValvtectValvTect Petroleum Products offers  a product called “Diesel Guard Heavy Duty/Marine Diesel Additive”. The company states that this additive stops corrosion, makes filters last longer, and decreases air pollution, among other benefits. It also enables ships to travel longer distances on the same amount of fuel. A different version of the product is “Marine Diesel Additive with BioGuard”, which is intended to also stop algae and bacteria from growing in fuels. Biocides are particularly useful in hot, humid weather.

Overall, your choice of marine fuel and additives will largely depend upon the type and age of your boat engine, the cost of different fuels, the climate you operate in, and the options available at a given port or marina. You might also decide to take environmental and geopolitical issues into consideration.

1. Marathon Oil
2. Chevron
3. Shell
4. ExxonMobil Corporation
5. Amnesty International
6. Environmental Protection Agency
7. BP
8. The Port of Los Angeles
9. “Everything About Marine Fuels”, Chevron
10. ValvTect
11. State of Oregon
12. USA Today
13. Boats.com
14. Irving Oil


Related posts:

  1. Marine Fuel Brokers Can Save You BIG Bucks!
  2. Marine Fuel Gauges on Boats
  3. Marine Gasoline | Boat Fuel Price Report for US & Caribbean
  4. Boaters Feel Marine Gasoline Prices


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