Originally Posted by FF
Learn to flair copper tubing and buy a coil and real fittings.
You will never go back to plastic.
For most of us it makes sense to go with what is already installed in our boats unless it's a real problem.
I wouldn't suggest repairing a failed PEX fitting by adapting it to copper.
PEX, when properly installed would seem to be the best water tubing for a boat. It will not corrode and it will withstand a light freeze, something copper will not do. It's also easy to fish through confined spaces. It has an excellent track record in residential use and in boats.