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Topics of interest to boat builders, repairers and owners. Subjects discussed by boating groups and forums.

On this page are issues that cause a lot of discussion pro and con in the boating community. These are my opinions. As with most things, there are two sides to every issue. I hope that these will give you food for thought and maybe contribute to a better understanding of the issues involved.

I will also post links to other online discussions or information on the subject. These will be included in the article or immediately below the article.

To print this page go to the bottom of this page and click on the link to the pdf printable versions. Please remember this is copyrighted material and if you wish to use it please e-mail me for permission. Contact Me

Itís a Gas:  The new EPA fuel systems on recreational boats, portable and permanently installed.

All boat manufacturers in the US, and boats imported into the US, that have gasoline fuel systems, are now required to have fuel systems that comply with the US EPA requirements for evaporative emissions.  What are evaporative emissions?   They are fuel vapors that escape from gasoline while you are fueling, from fuel tanks through vents and permeable tank walls, and from the permeable hoses and fittings in your fuel system. 

Prior to the EPA rulings, the US Coast Guard was primarily concerned about the safety aspects of fuel vapors. So, the Coast Guard established standards for how much vapor could escape from hoses and plastic (polyethylene) gas tanks.  These were based on how much vapor it would take to get to the lower explosive limit (LEL), a mix of fuel vapor and air, to cause an explosion if there was a spark or other source of ignition.  If the amount was below the LEL the explosion would not occur. This was one part of a three part effort to eliminate fires and explosion by preventing leaks, eliminating sources of ignition, and providing adequate ventilation of areas where fuel vapors could collect.  Those permeation standards have been in affect since 1978.

Enter the EPA, the Clean Air Act, and the legitimate concerns over air pollution and Global Climate change.  The EPA in the early 2000ís proposed regulations that would limit the amount of emissions from recreational boats to an amount far less than the USCG regulation allowed.  This resulted in much debate, research, and manufacturing processes. To keep a long story short, the new EPA standards went into effect in 2012.  See

These rules made dramatic changes to how fuel systems were configured.  On some boats they mandated carbon canisters in the vent system, automatic valves to keep pressure in the tank below 2 psi, and differences in how hoses are constructed.  Manufactures of tanks, hoses and other fuel fittings devised ways to comply with the new rules. The American Boat and Yacht Council revised their fuel system standards to provide means for boat and fuel system manufactures, to comply with the EPA regulations.  See

However, permanently installed fuel systems were not the only systems affected.  Portable fuel tanks, primarily used for outboard motors, were affected along with small portable fuel containers.  I will not discuss the small portable gas cans.  I will discuss the portable tanks used as fuel tanks for outboard motors. 

Portable systems used for outboard motors were not regulated by the US Coast Guard, but have long been built by standards published by the NFPA and ABYC.  Those standards did not cover emissions, but like the Federal standards for permanently installed systems, were concerned mainly with safety, i.e. prevention of fires and explosions.

So, what are the issues?  The main issues are, pressure develops in these systems (itís not supposed to) and they leak, usually at the fittings, and the plastic tanks expand due to pressure in frightening amounts. 

In boats with a permanently installed system, the vents, that are supposed to keep the pressure below 2 psi, often clog raising pressure in the system.  During filling, fuel fills back up, resulting in overflow of the fill, spilling liquid gasoline or causing very slow filling, or incomplete filling.  This also results in fuel feed issues, which causes engines to not start or stall when underway. This in itself can be a safety issue if the engine stalls and refuses to restart when the boat is a perilous postion such as entering an inlet, crossing a bar, in a river with a rapid current, when docking or maneuvering, or when in heavy traffic in a narrow channel.

These problems are both a safety and an emissions issue, and they are very frustrating to the boat owner.  They realize the safety issues but do not understand why the the emissions issues are appearing to be more important than the safety isssues. They simply want a safe way to get fuel to the engine, so the engine runs safely and reliably.  Anything that interferes with that is not good.

Portable tanks have the same issues, leaky fittings.  Tank manufacturers of portable tanks are using push-on type fittings that do not require clamps or swaged fittings to work.  Often the tanks leak at these fittings when pressure develops in the tank.  Many dealers and professionals advise using aircraft quality cement to seal the fittings, which, while solving the problem, defeats the purpose of the convenience of a snap on fitting which can be quickly connected or disconnected and easily replaced.  Owners have resorted to replacing the caps on these tanks with old style vented caps used on earlier model portable fuel tanks, effectively defeating the purpose of reducing emissions. 

So, what are the solutions? At this point, there are none.

The EPA needs to review the regulations, study the problems, and try to find some reasonable solutions that eliminate the problems while at the same time preserving the evaporative emissions requirements.  The Coast Guard needs to work with the EPA on finding ways to solve the safety issues. 


© 2021.  All rights reserved.  Created 03/16/2021


Links on this page will be moved to Ike's List when the topic is changed.

Hottopics! Downloadable PDF files. This is copyrighted material.  You may download and print these for your own use, or for educational purposes, but not for commercial use.

Battery Group Number: Does Size Really Matter?
Batteries and Chargers
Grounding. Our connection to the earth.
Grounding an Outboard
Portable Generators On boats. Pro and Con?

Carbon Monoxide:

Sophias Law and Carbon Monoxide

NPR Article on; Carbon Monoxide Poisoning From Portable Generators Proves Predictable and Deadly


Corrosion On Boats

Safe Loading and Capacity
Boat Load Capacity VS Available Seating and the Formula for Persons
How Many People Is Too Many?
Stability on Small Boats
Horsepower and repowering.

Other Subjects:

Itís a Gas:  The new EPA fuel systems on recreational boats, portable and permanently installed.
HIN 101 For Boat Owners Rev2.
Fiberglass over wood or not?
Aluminum Tanks and Boats: To Paint or Not to Paint?
Much Ado About Ethanol
Ethanol Vs Isobutanol

American Boat And Yacht Council  Boat Design Net  Wooden Boat Foundation
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