how to seal a leaking propane ferrel?

[foufou]

All the stoves I have installed have pipe thread as do the line from the tank. A flare adaptor is the fitting that joins the two. The best joint compound in the US is Rector Seal. The flare fitting should not need joint compound unless it has been damaged in which case joint compound might work. Automotive gasket sealers would do if the plumbing sealers are not available. "Jumping Jack Flash" "It's a Gas"

[Redpcx]

Ferrules rarely leak, most likely the tube is cracked.
Yellow teflon tape is thicker than white. Both are equally resistant to most chemicals, the thicker one is just colored so gas inspectors know you didn't use the really thin stuff.
If the ferrule you refer to is a brass compression ring, check vigorously to see if the metal tube is cracked. If it is, cut off the crack, slide the nut up the tube and wind string or teflon packing or teflon tape around the tube so it will form a packing to be be compressed when you tighten the nut. This packing will take the place of the ferrule. Check for cracked tubing!

[boatpoker]

Originally Posted by Redpcx

wind string or teflon packing or teflon tape around the tube so it will form a packing to be be compressed when you tighten the nut. This packing will take the place of the ferrule

Wow ! try and get that past a licensed pipe fitter.

[Skuzzlebutt]

This might be obvious, but...

Many, if not most, islanders use gas of one sort or another for cooking. Second, they are most adept at 'making do' with whatever is at hand.

I'd suggest just asking a couple of locals. Pretty sure you'll find a solution.

CAUTION: Watch how they do it, and check carefully for leaks. If it looks questionable, thank them, then throw out their solution.

CAUTION #2: It is common in the islands to check for leaks by holding a lighted match near the connection. This might be acceptable in a rented apartment, but not on a boat.

[buzzstar]

Originally Posted by Cadence

You are playing a dangerous game looking for a half assed fix on a propane leak. A new fitting and inspect the tubing which ages and gets brittle/crystalline. I would hate to see you burnt to the water line,

I completely agree. A very, very dangerous game. I too would hate to see you burned to the water line, and it could happen to your boat as well. Seriously, shut down the source until you are able to get a proper fix for the leak. Find an alternative method of cooking or eat cold food (or heat it on the engine?) until it is properly repaired. I am not saying a temporary repair as suggested elsewhere will not work; it may well, but if it does not the consequences can be terrible for you and others. Still, the choice and the responsibility are yours.

[NorthCoastJoe]

First a leak could blow you out of the water. I am a ex firefighter and have seen what propane can do.

To me the best emergency fix would be to get a couple of barb fittings and some propane hose. Remove the problem fitting and thread in the barb fitting with pipe dope. Do this at both ends and then install the hose and clamp it. Check for leaks and be sure to shut off the propane when you are not using it.

[slowpoker]

Yes, I would not just patch this section of tubing unless it is necessary, only temporary and if using some of the ideas given by others in these posts.
Something made the tube or something crack right there at that point because of flexing or vibration.
You should fix it permanently by eliminating flex by using flexible hose or supporting tubing rigidly at that point and junction.
If at the stove; get a short, threaded propane rated hose section and attach to the stove and the other end of the hose attach somehow to a newly cut section of the existing copper line. But....There should not be any joints or connections along the feed line while inside the hull, except at the stove, then exiting the hull, at the regulator before the tank itself unless the joint or connection is sealed in a compartment that vents down and out near the waterline outside the hull. But....you should prevent the flexing at the point you got the tube or ferrule to crack, prevent that flexing of the copper tubing there, either sagging and not supported or swinging of the stove caused the crack and the dangerous leak.

[lordlefrog]

here is what happens to a boat with a propane leak:

https://www.youtube.com/watch?v=Yxm3uMy6MPI&t=2s

[Dockhead]

Originally Posted by Cadence

You are playing a dangerous game looking for a half assed fix on a propane leak. A new fitting and inspect the tubing which ages and gets brittle/crystalline. I would hate to see you burnt to the water line,

Good God yes. Don't mess around with this. Replace the entire line and fitting and be sure that it is totally gas tight, before using it. If you can smell gas inside your boat, get out! Yikes.

[a64pilot]

See if possible to get an alcohol or other type of liquid fuel camp stove until you can get the other fixed, if Coleman fuel, use it on deck.

[Three Sisters]

It appears the OP has flown the coop