Fed. Seaworthiness Regulations on Recreational Boats >20ft & <65ft?

Show me the rules for outboards.

 

https://www.uscgboating.org/regulations/assets/builders-handbook/FUELSYSTEM1.pdf

For example, fuel systems for outboards are not here. Did I miss them somewhere else?

 

Not that I'm aware of. That could be regarded as a deficiency in the rules. It may also mean that the USCG has not seen many major incidents due to problems with fuel systems in outboard powered boats.

 

It would be a mistake to consider the USCG regulations on recreational boats as a design guide.

 

Sort of my point. We are at full circle.

 

Outboard portable fuel tanks are not properly addressed on modern, high powered boats. They are based on small open boats with little or no accessories.

 

New boats in the US also need to meet the applicable EPA regulations on engine and gasoline fuel system emissions. Engine emission regulations require any engines installed be certified by the engine manufacturer as meeting the relevant standards. New portable gasoline tanks and fuel lines for boats can only be sold in the US if they meet the EPA regulations so a boat builder does not need to do anything to meet the requirements for portable tanks. The rules for permanately installed gasoline fuel systems can be met by installing a system using components certified by the manufacturer as complient. Metal tanks are deemed complient.

 

Metal gas tanks need to be certified. They are not automatically compliant.

 

From an NMMA document of the fuel tank rules (underlining added) https://www.nmma.org/assets/cabinets/Cabinet55/Evaporative_Emission_FAQs.doc :

Are metallic fuel tanks covered under this rule?

Yes, metallic tanks are subject to the permeation standard, but as long as the gaskets, fittings and cap meet the criteria, then the tank can be deemed certified or design certified for permeation. The distinction between metallic tanks and non-metallic tanks is that with metallic tanks emissions do not permeate through the tank wall. Boats with metallic tanks must also comply with the diurnal and fuel line and fuel system component requirements.
​

Added: The comments above are for the EPA permeation regulations. Metal fuel tanks will also need to meet other EPA regulations and any applicable USCG regulations with may require certification of conformance with the USCG regulations.

 

ABYC document from USCG website on fuel tank regulations: https://www.uscgboating.org/assets/1/AssetManager/ABYC.1002.01.pdf

Ike's New Boatbuilders Home Page aka Everything Boat Building is an excellent resource for anyone interested in boatbuilding. https://www.uscgboating.org/assets/1/AssetManager/ABYC.1002.01.pdf It covers US regulations and also has suggestions of additional standards which should be considered.

 

For fuel the regulations can be found:
33 CFR 183.5XX
46 CFR 182.435
ABYC H-24
ABYC H-33