Dennis Pogson wrote:

Dunno what country you are in, but in the UK, there are regulations which
would virtually FORCE you to use copper tubing along the whole length of the
run, except at the ends, where a short piece of rubber or armoured rubber is
permisible because of movement and/or ease of connection.

I find it hard to believe we are alone in this recommendation, sure all
countries with large leisure fleets must have similar regs.?

The ABYC standards, which in many aspects are also the legal standards
(I'm not sure about propane, but I would guess it is), permit both
copper and flexible supply lines. My boat was built in Canada, as was
my previous boat, both use flexible hose throughout. Copper must be
flared, hose fittings must be permanent. Compression fittings are
specifically not allowed, and I think hose clamps would be frowned
upon. One line for each appliance, no joints other than at a flexible
section near the appliance.

There must be support, protection against vibration, etc. Its worth
looking over the rules if you're running new lines, it might even be
worth it have a surveyor bless the system. GBM - I could send you
part of my copy but its 13 years old, and they were revised in 2000.

As for removing the old hose, if there is access, you can use a one
inch flat drill bit and a long extension to ream it out and start anew.