Help wanted with gas fittings on boat

jdc said:
It's not clear from the text or photo, but I think the brass fitting is probably in two parts so one can turn the nut without having to turn the hose, ie one of these

https://www.pipekit.co.uk/brass-f-f-seat-w-washer-sw-nut-bspp-x-hose-tail-3-8-x1-4-.html

At less than £3 each I'm not sure I'd re-use any bits!
Click to expand...

I agree with you .... at that price I'll just buy two new fittings. :)

The fitting in my photograph does have a spinning nut part so your link is very similar if 3/8 x 1/4 means that the thread is 3/8 and the 1/4 is the ID of hose which the spigot is designed to push into .... but I'm not clear about that?

However, your link seems to have a flat surface and a washer whereas the part I need must have a domed/conical internal shape without a washer as it has to fit onto the cooker at one end and the regulator at the other.

Richard
 
I always assumed, perhaps incorrectly, that the tubing used as a sleeve was effectively, part of the gas locker.

At least on my boat, the plastic tube goes all the way back into the gas locker and is open at that end. The copper pipe is fed through it to near the cooker. The end of outer tube is then sealed to the copper pipe with what looks like Sikaflex.

I always assumed the idea was that if the copper pipe corroded and leaked, it woudl travel back up the outer tube to the gas locker, and then overboard, rather than getting into the bilges.
 
rszemeti said:
I always assumed, perhaps incorrectly, that the tubing used as a sleeve was effectively, part of the gas locker.

At least on my boat, the plastic tube goes all the way back into the gas locker and is open at that end. The copper pipe is fed through it to near the cooker. The end of outer tube is then sealed to the copper pipe with what looks like Sikaflex.

I always assumed the idea was that if the copper pipe corroded and leaked, it woudl travel back up the outer tube to the gas locker, and then overboard, rather than getting into the bilges.
Click to expand...

On my boat, the rubber pipe leaves the gas locker high up the side near the top of the locker. It exits through a screw gland which is tightened so that a sealing gasket clamps around the pipe and forms a tight seal so containing any gas within the locker which is vented directly to the open sea below.

The rubber pipe on the other side of the seal wends its way for a metre or so before it enters the conduit pipe.

Richard
 
So if the rubber pipe developed a leak, the gas woudl end up where?

On my boat, it would end up back in the gas locker. Perhaps extend the conduit all the way back to the locker and seal the end in the galley where the rubber pipe exits?
 
rszemeti said:
So if the rubber pipe developed a leak, the gas woudl end up where?

On my boat, it would end up back in the gas locker. Perhaps extend the conduit all the way back to the locker and seal the end in the galley where the rubber pipe exits?
Click to expand...

I suspect that on the majority of boats with gas, if the pipe fails it ends up in the boat and hopefully persons on board will smell it. I suspect that the majority of leaks are from the bottle area which is why they like to see bottle storage well vented and sealed off from the rest of the boat.
 
rszemeti said:
I always assumed, perhaps incorrectly, that the tubing used as a sleeve was effectively, part of the gas locker.

At least on my boat, the plastic tube goes all the way back into the gas locker and is open at that end. The copper pipe is fed through it to near the cooker. The end of outer tube is then sealed to the copper pipe with what looks like Sikaflex.

I always assumed the idea was that if the copper pipe corroded and leaked, it woudl travel back up the outer tube to the gas locker, and then overboard, rather than getting into the bilges.
Click to expand...

That sounds like a great secondary purpose for the clear plastic tubing/sleeve... On board my Moody it's a similar sleeve although I'm not sure on the opening at the locker end..

Does sound perfect though - any leak in the copper will head out into the draining gas locker instead of into the bilge :)

We should also recommend adding a bubble leak detector at the bottle end of the hose as well.. Then any leakage can be tested for each and every time the gas is switched on.. and in between times if you wish.
 
Boathook said:
I suspect that on the majority of boats with gas, if the pipe fails it ends up in the boat and hopefully persons on board will smell it. I suspect that the majority of leaks are from the bottle area which is why they like to see bottle storage well vented and sealed off from the rest of the boat.
Click to expand...

Indeed so. If my gas pipe fails after it leaves the locker gland the gas ends up in the bilges.

Richard
 
Martin_J said:
We should also recommend adding a bubble leak detector at the bottle end of the hose as well.. Then any leakage can be tested for each and every time the gas is switched on.. and in between times if you wish.
Click to expand...

I'll investigate whether I can fix one of those in the gas locker. I'll probably also change the regulator as that is the same age as the main rubber pipe. The only bit that I have changed was 3 or 4 years ago which was the rubber flexible hose between the regulator and the bottle itself inside the locker as that was also rock hard and made changing cylinders rather tricky. The new pipe is still very flexible.

Richard
 
Martin_J said:
That sounds like a great secondary purpose for the clear plastic tubing/sleeve... On board my Moody it's a similar sleeve although I'm not sure on the opening at the locker end..

Does sound perfect though - any leak in the copper will head out into the draining gas locker instead of into the bilge :)

We should also recommend adding a bubble leak detector at the bottle end of the hose as well.. Then any leakage can be tested for each and every time the gas is switched on.. and in between times if you wish.
Click to expand...

Think about another failure mode. Large leak in the gas locker will try to drain from the locker drain but may also migrate down the afore mentioned tube and enter your boat wherever that tube ends. Maybe sealing the inside accomodation end and leaving the locker end open is the right answer.
 
greeny said:
Think about another failure mode. Large leak in the gas locker will try to drain from the locker drain but may also migrate down the afore mentioned tube and enter your boat wherever that tube ends. Maybe sealing the inside accomodation end and leaving the locker end open is the right answer.
Click to expand...

Just as Rsezmeti described back in post 25?
 
Last edited:
Richard. What you seem to have there is a gas system built to USA standards where it is normal to instal systems using pre assembled pipes and fittings in an assortment of lengths which one just screws together to get a system and where long runs of these approved hoses is normal so long as installed in an approved manner. If sailing overseas it might be worth checking the views of local surveyors. Here in the UK many surveyors do not like these systems and use such expressions as only use hoses of minimum length with copper pipe for long runs. Copper pipe for long runs is fine but then folk start talking about bulkhead fittings of which there could be many and this could introduce two compression joints at each bulkhead and two possible sources of leakage. However this is easily fixed by drilling the bulkhead connectors all the way through at pipe or size and then the pipe can be threaded through and supports the pipe as required. This is one of the advantage of the hose as it is a single length. If you go to the on line pages of West Marine you will see the range of pipes and fittings used and if you put your question onto the appropriate forum within Cruisersforum.com where people familiar with hose systems can offer help especially how bulkheads etc are correctly dealt with. I personally prefer the hose system however I know I would have problems getting my local surveyor to write a report using words that would satisfy my insurers. :)
 
Don't underestimate the ability of copper to work harden and fail under stress, you have to be very sure that it isn't vibrated next to something hard.
Also, I came across a thick wiring loom cable laying in the bilge, it wore down considerably from the boat rolling.
 
fisherman said:
Don't underestimate the ability of copper to work harden and fail under stress, you have to be very sure that it isn't vibrated next to something hard.
Also, I came across a thick wiring loom cable laying in the bilge, it wore down considerably from the boat rolling.
Click to expand...

That is why various rules refer to max unsupported length. Less chance of vibration induced work hardening. One advantage of the hose solution though hoses have a best before date at which they should be replaced.
 
fisherman said:
Don't underestimate the ability of copper to work harden and fail under stress, you have to be very sure that it isn't vibrated next to something hard.
Click to expand...

That's the exact reason I piped my LPG with 3/8" sched 10 steel tube. All the screwed fittings were welded after finish fitting. The pipes welded to the boat frames and all pressure tested to 60 psi.

The inside will not rust as there is no oxygen inside and the outside was grit blasted at the same time as the inside of the hull then painted and sealed in insulation.

The only flexible piping is where the appliances are with a flexible pipe between the isolation valve an the end of the steel pipe and the appliance input connector.

All the hydraulic steering and actuators piping were done in the same way.
 
Bilgediver said:
Richard. What you seem to have there is a gas system built to USA standards ....
Click to expand...

Yes, that's correct. The boat is built in South Africa but to USA standards, so no double clipping of water hoses etc.

I've found that I can buy long lengths of gas hose so will now look for the end fittings just in case I can't use the existing ones. I'm thinking of replacing the regulator and solenoid valve but trying to work out the best way to join all the components together is rather a puzzle. :confused:

Richard
 
RichardS said:
Yes, that's correct. The boat is built in South Africa but to USA standards, so no double clipping of water hoses etc.

I've found that I can buy long lengths of gas hose so will now look for the end fittings just in case I can't use the existing ones. I'm thinking of replacing the regulator and solenoid valve but trying to work out the best way to join all the components together is rather a puzzle. :confused:

Richard
Click to expand...

Robertson and Caine in Cape Town

If I wish to remove any fittings from flexible hose I slit the hose with a knife along the length of the inserted part of the fittings and the fittings then can be prised from the pipe.

If there is a metal hose crimp or worm clip this is removed first. I remove the metal hose crimp by using a hack saw and saw diagonal across the hose crimp and then prise it off.
 
Just to bring this thread to a close almost 12 months later ..... the search for the fittings I needed for each end of my gas pipe proved impossible. I now have a collection of fittings of various shapes, sizes and threads but none of then are direct replacements for the existing fittings on my boat.

It appears that the fittings on my boat are not used for gas in Europe but seem to be hydraulic line fittings used on HGVs or something. I did finally manage to find a fitting with the same female concave shape of the same size and with the same thread but it is impossible to find all that with a 1/4 in / 6mm / 6.3mm hosetail. I will therefore have to increase the size of the pipe to 10mm to match the fitting below and hope that it will go through the bulkhead fittings without too much dremelling.

I guess the the answer is not to buy a boat built in the southern hemisphere if you want standard fittings. :(

IMG_7741.JPG


Richard
 
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