plugster wrote:
The diesel fuel tank on my boat is in the center of my boat just forward of
the mast and the engines are in the back so the fuel lines pass through the
cabin. There are no fuel leaks, the lines are made from a gray rubber and
smell strongly of the diesel fuel. The boat is 6 years old.

I'd bet the fuel lines are not an ABS-ABYC approved type for fuel.
Proper fuel line is expensive, but it lasts considerably more than 6 years.

... The runs are
about 45 feet and they do a fair amount of twists and turns. I am thinking
about replacing them with soft metal tubing, maybe copper (Home Depot water
tubing) or 3003-0 aluminum (aircraft grade fuel line).

Don't use aluminum on a boat. It corrodes far too quickly and is more
difficult to make up joints. Ask me how I know!

Refrigeration grade copper tubing (type L or M IIRC but check the specs)
is acceptable as fuel line... but it's difficult to install properly.
Unless you can rip out all obstacles, you have to snake it into place
and then mount it properly (it will work harden with vibration, and then
leak no matter what) and make up the terminal connections. This takes a
lot of time and careful work.


...Of course I will
leave a short flexible part near the engine for vibration.

You might as well go with the more expensive fuel hose for the whole
run. I'd recommend that, and I just did a somewhat shorter simpler job
on our trawler this past spring. Of course I work with tubing (HP air &
hydraulics, among other things) almost daily so the joint connections
were not a problem.

It'll cost more in dollars for material but take far less time & trouble
to install, and will be far less likely to leak due to bad joining.

Fresh Breezes- Doug King