Fuel line material

[Liambennett]

Hi all,
Just about to redo all the fuel lines.
What material is best ?
My father is an old school marine engineer and wants to use stainless, he is an excellent pipe bender !
From what I gather most propel use flexible type hoses these days.
Any suggestions?

 

[O C Diver]

For me, it would somewhat depend on vessel size, length of runs, and how open the passage ways are. I replaced all mine during my 2015 refit with USCG approved rubber fuel line.

Ted

 

[Liambennett]

It’s only a 45’ single engine Cummins.
There will be negligible cost difference as we have both materials, just wondering what’s best

 

[RT Firefly]

Greetings,
Mr. L. Listen to your father. SS will never degrade or delaminate. The only problem I can foresee is the rigid tubing cracking due to vibration BUT proper bracing should minimize/eliminate that risk.

 

[Barking Sands]

I redid a portion of my fuel system last year. I reviewed the ABYC fuel section and I did not see SS listed as a material. I had planned to use stainless as well. I chose against only due to possible future surveys for selling the boat.

H-33 7/21© 2021 American Boat & Yacht Council, Inc9 33.14.3 A shutoff valve is required at the fuel tank in gravity feed systems.33.14.4 In systems where fuel may siphon, 33.14.4.1a valve shall be located where it will stop siphoning, and 33.14.4.2fuel lines between the tank and valve shall be secured above the top of the tank with clips or straps capable of withstanding a 2.5 min fire test, and 33.14.4.3manually operated valves shall be readily accessible. 33.14.5 Electrically operated fuel pump(s) shall be connected to be energized only when the engine ignition switch is on and the engine is running. A momentary type override (five seconds) is acceptable for starting.EXCEPTION: Electrical fuel pumps used to transfer fuel between tanks. 33.14.6 Fuel distribution, return, and transfer lines shall be flexible hose or metallic pipe. 33.14.7 Flexible hose shall be USCG Type A-1, A-2 or A1-15 (see TABLE 1) if the line is within an engine compartment.33.14.7.1 All fuel distribution and return lines located outside the engine compartment shall be of the type specified in H-33.14.8, or 33.14.7.2 shall be USCG Type A-1, A-2, or A1-15, or 33.14.7.3 USCG Type B-1, B-2, or B1-15 if a break at any point in this system will result in the discharge of no more than five ounces (147 cc) of fuel in 2.5 min when the hose is severed at the point where maximum drainage of fuel would occur, with the boat in its static floating position and fuel system filled to capacity.33.14.8 Metallic fuel lines shall be aluminum or copper alloy pipe of no less than schedule 40, or33.14.8.1 copper alloy tubing with a nominal wall thickness of at least 0.032 in (0.81 mm).33.14.9 Rigid fuel distribution lines secured to hull members shall be connected to the engine by a flexible section.33.14.9.1The rigid line shall be supported within four inches (101.6 mm) of this connection.

 

[Comodave]

I would use the proper fuel hose for your application. The rubber hose is supposed to be better in a fire than copper. Don’t know about S/S. But the rubber is simple to work with and approved. You definitely want to use an approved material so your insurance company will be happy as well as any future surveys.