BBQ's onboard - safe or not - fuel breathers

[ozscott]

Someone on the thread about what you would change on your boat mentioned fuel smell and BBQs. Its somthing I have pondered on and off for a while. I have breather pipes running from my underfloor tanks to a copper pipe on the transom and from there out through the transom to vent above and to the side of the engine - ie above the water line. I have never once smelt fuel smell. But there must be times where there is some vapour creeping up even if the wind shoots it off.

I see people with (mainly gin palaces) BBQ's on their rear rail near the transom - hanging out over the water a bit. I would love to stick a little one on for over nighters, but I am parranoid that fumes could come up and ignite.

I know that there is a saturation point of fuel vapour versus air - thats the way the bilge meters work and wont let you start the engine if the air is too saturated. I would have thought that to be flamable, you would need to have enough to smell it..perhaps to smell it quite a bit. I dont know. Any comments appreciated, particularly from those who still own their own eyebrows.:-*

Cheers

[PinHead]

I used to have a 3 burner gas stove inside the 20' half cabin we had many years back..never a problem.

I have a barbie on the stern rails now..have not even used it yet but no problems...I do not have a fuel breather as described by yourself.

[ozscott]

where is your breather mate?

[PinHead]

a very small one as part of the fuel filler cap

[bastard]

Ive got a rod holder mounted webber,i dont think heat beads could set it of but im still worried,about every 20 minutes you get a woft of fuel,its a 500ltr fiberglass tank,i thought maybe there is some sort of filter that can be placed in the fuel breather line.Any help would be appreciated as its neally time to sit out the back deck and fire up some smoked tailor.

[ozscott]

thats a big tank bastard...ahhh fresh slurried taylor...very underated fish!

[ozscott]

...thing is you have to light the beads...flame has to be introduced at some stage..bugger

[ozscott]

im assuming Pinhead that your fill cap is located around the transom? - ie does it vent within 2-3 metres of the Barbe

[tigermullet]

If the BBQ is higher than the vent then the chances of breaching the fuel/air saturation point would be very small. Fuel vapour is heavier than air and will, naturally, sink. In order for the vapour to rise to the level of the ingnition source it would have to be forced to do so i.e., by wind and I doubt that the saturation point could be reached.

However, it is a worry and if there is any doubt it might be better to re-locate the BBQ or the fuel vent. With any ignition source there is always the chance that an ember could fall into the vapour zone and give spectacular results.

The whole problem with fuel vapour and boats is that you generally don't get second chances and the first mistake is liable to be the last.

I hope that you can find a comfortable solution to the problem and the only thing that I can offer would be the suggestion that the vents be placed as low as possible to the water line (positioned in a manner that vapour cannot accumulate in the rear deck or cabin space) and the BBQ to be placed as high as possible.

Other than that...Beer and peanuts?

[Shanoss]

Cooked up a couple of eye fillets on my boat the other night on a charcoal weber. They were divine, and the only worry was Leezor (Ausfisher) thinking a piece of bread was a good trade for said steak.

[Roughasguts]

Yes,, transom fuel vents and the barbie, have always made me think what gives here, are there set down regulations for safety or are they illegal, got me stumped, would like to know me self.

If you look at fuel stations the fuel tank vents for the tanks are around 10 foot high. I guess the fumes do still go down but must disperse to a non combustable ratio, ain't nothing high tech about those vents.

[bastard]

What i think i will do is rotate the breather 90 degrese so the outlet is pointing down instead of backwards towards the boat,also ill clip the covers on the side of the boat the breather is on when i use the bbq,i honestly thought there would be some sort of inline devise for this probleme,cheers Bastard.Also i was told lpg vapour falls and fuel vapour rises,but i dont know which is true.

[tigermullet]

No - both fall as both are heavier than air. You can see this on a calm day by filling a small glass jar with petrol, place outside in the sun and you will see the vapour pour over the sides and flow down the outside of the jar.

That is why large boats have bilge blowers - the vapour will collect and concentrate in the bilges. One spark and you're an orange/yellow flash on somebody's horizon. Not nice!

[PinHead]

the set up on mine:

damn..how do u post a pic now

[Roughasguts]

the set up on mine:

damn..how do u post a pic now

When you find an easy way PinHead, let me know.

[PinHead]

another try:

[bastard]

I can see the fuel cap,but were is the fuel breather located.

[PinHead]

a small hole in the filler cap is all..no other breather required.

[bastard]

a small hole in the filler cap is all..no other breather required.Do you ever smell fuel vapour out of there,it never used to bother me but last year as we fueled up and were ideling out of horizon shores we hurd an explosion and it was the boat after us,that night on the news they showed how burnt the little girls legs were and it still sits in the back of my mind.

[PinHead]

I have not smelt any fuel vapors at all at any time...I am always safety conscious..after fuelling I always lift the engine hatch and have a sniff...run the bilge blower and make sure no one is onboard other than myself when I start the motors...plus..I regualrly inspect the fuel lines etc.

[Essence]

Just to chime in. On Whittley's generally the bbbq's are out on a duck board, away from fuel breather. On Dreamdays, the fuel breather is fairly low in the transom, BUT!! on calm nights, you can smell the fuel, hence it now has a fan on the dashboard, bit like the old combi fan, run alls night (7amp battery)and is aimed down to blow any vapours off the back. The bbq is mounted on the side, away from fuel breather, and when it is lit, the fan is already turned on. Simple but a bit of piece of mind.

[ozscott]

Essence - great idea. My BBQ should go on the bait board which sits above the transom, and the breather holes are a foot aft on the transom walls in the splash area (but not prone to splash the way they are set up - they are high etc) ...fan is a great idea.

Cheers (if you are still listening!).

[Fed]

ozscott I think the wire gauze on breathers is a spark/flame arrestor type of thing, you could probably hold a cigarette lighter under it with causing an explosion. Same would do for Pinhead's pinhole.

I'm not going to test it though.

[WalrusLike]

I have breathers in the transom directly under the portable stove we use on the bait board..... But I have never smelt fuel there. (apart from when I forget that I can only fill at a snails pace so the fuel bubbles up the filler into the motor well)

I am not so sure about the heavier than air thing.... I think I can recall upward vapour at fuel bowsers.... Will check again at next fill.

This is something I would hate to get wrong..... But without any smell I feel fairly safe using the stove where it is.

[ozscott]

I think saturation levels have to be high for combustion. Cheers

[rowanda]

fuel vapours (and LPG) definately go down and are heavier than air

[WalrusLike]

If they are going down then putting the stove on the bait board should be ok because it's much higher than the breather outlets.

Speaking of breathers..... Why are the rubber hoses in the transom for mine always wet with condensation? Is it because evaporation causes cooling? If so why would the tube be wet... Wouldn't the tank be the thing getting cooled? The hose only has the vapour... It's the liquid it left behind that gets the cooling effect.

So many questions..... My Dad used to get sick of them... And now it's your turn. :)

[thylacene]

To answer the question of whether a gadget exists, check this out https://www.whitworths.com.au/main_itemdetail.asp?item=13520&search123=Flame+arrestor&intAbsolutePage=1.

Cheap peace of mind if you want open flames on a boat. Actuall don't know if it is cheap, but it is pretty.

That said, they look awfully like a gadget they were flogging here some time back as a sacrificial fuel additive to raise the octane levels. Porous stone filter between 2 barb fittings, might have to go hunt the sample I was provided and try to light it up ( in the driveway, not in a boat), I know it did nothing for performance based Dyno tests.

[Chimo]

RAG /PH

http://www.irfanview.com/ is the easiest way to resize pics and then just follow your nose when you go advanced to post on AF.

I've got two vents on the transom of the Vag and I've used a gas stove with flame to boil water and fry in a pan above the vent on the cutting board without any issues.

IMHO the air / fuel fume ratios are well off the danger scale given the fact the vents are lower, any fumes will fall and there is always way too much breeze running off to the stern ie away from the boat for thete to be a bang!.

Even when you try to cook its often too breezy to maximize heat for cooking. Ditto cooking on a bbq on the rear deck of a Perry cat at anchor, the flame often blew out with the slightest of breeze. They are diesel so no chance of a bang just an example.

Cheers
Chimo