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Are you leaving the "gate" valve open on top of the can? Are you using the rubber seal when the stove is not in use?

If you follow the instructions for use, you should be fine.

And if I don't?

If you are letting the canister evaporate freely into the boat while its closed up, then it becomes a math problem to establish whether an entire canister in the bilge volume constitutes a problem (zero ventilation case). If that's not a problem, you can forget it.

Got any idea what the bilge volume is in cubic feet? And how much alcohol does the canister hold?

No I don't - but my wife uses the stove all the time and she does not bother about it when it's full - we never think about it - no one ever said that the fumes from the stove go into the bilge and make fires - never heard that one before in 40 years.

BOAT wrote: ↑Thu Mar 05, 2020 10:11 am Well, there is this big round thing inside my stove with white stuff that soaks up alcohol - I pour a LOT of alcohol into that thing! Like almost a half a can!! So your telling me that when I am not using the stove that thing is creating fumes all day that are going down into my bilge?? Is that not a bad thing?? There is nothing in the stove instructions that say I can't leave the stove full all day - is that dangerous??

If you leave the canister open all day, methanol vapor will be coming out of the canister (assuming it's a normal sunny day). Depending on conditions such as wind speed, temperature, openings in the boat, etc., some or all of these vapors could wind up in the bilge. Try to find one record of a bilge fire resulting from a non-pressurized alcohol stove that doesn't involve a spill.

Also, the relative density of methanol to air is 1.1. So, while it is heavier, it won't just fall out of a breeze.

In a static case (no dilution), if you vaporize a tea glass of methanol in the bilge, and light a match in the bilge, you would likely be able to ignite the vapor. This is based on quick napkin calculations, and several assumptions, so take it with a grain of salt. Not sure how much of a whoosh you'd get. I've vaporized that much gasoline in a trash can and set it off with fairly dramatic results.

Jimmyt wrote: ↑Thu Mar 05, 2020 11:39 am If you leave the canister open all day, methanol vapor will be coming out of the canister (assuming it's a normal sunny day). Depending on conditions such as wind speed, temperature, openings in the boat, etc., some or all of these vapors could wind up in the bilge.

I've vaporized that much gasoline in a trash can and set it off with fairly dramatic results.

So, the bilge WILL explode - that's a very bad thing - I guess I can't leave my stove full - I'm gonna complain to the manufacturer. They never told me that - I don't want the bilge to have fire - fire is bad.

You should tell everyone else that they can't leave the fuel in their stove. We don't need no fires.

BOAT wrote: ↑Thu Mar 05, 2020 11:55 am So, the bilge WILL explode - that's a very bad thing - I guess I can't leave my stove full - I'm gonna complain to the manufacturer. They never told me that - I don't want the bilge to have fire - fire is bad.

You should tell everyone else that they can't leave the fuel in their stove. We don't need no fires.

The sad thing is, I can't tell if you're joking...

Keep your canister full. Close the control gate when it's not in use and put the gasket in place per the manufacturer instructions when you're not using it. Don't call the manufacturer. You will be fine.

Don't store open canisters full of methanol in your bilge. DON'T SPILL A BUNCH OF METHANOL IN YOUR BILGE.

The question you asked originally was unanswerable without a significant effort, and a bunch of assumptions. I reduced it to an easily analyzed extreme to give you an idea of what it would take to reach the flammable limit of methanol in your bilge with no other influences (basically the bilge sealed with alcohol inside).

Can you create a flammable concentration in the bilge with the amount of alcohol in the canister? Yes. Can you do it without doing something ridiculous, clearly violating the manufacturers instructions? No.

I'm actually looking into installing this type stove in my boat, as I feel it is a safe way to cook in the cabin. Seems like they are out of production though.

Well, if they make the bilge go boom then I can imagine why there are none available to buy anymore! Maybe they are just too dangerous to sell.

Have you tried a Coleman stove?

BOAT wrote: ↑Thu Mar 05, 2020 6:32 am If you leave the stove on unlit the fumers will settle into the bilges because propane is heavy. Propane exhaust is also heavy and goes down, not up.

Alcohol is lighter than air as a gas and will not go down into the bilges - it will float up into the air and out of the cabin. That's why it irritates your nose if you stand too close to the alcohol stove when it's on - even the exhaust on the alcohol flame goes up and makes your nose hurt.

I like propane much because it burns cleaner and does not irritate my nose, but I still use dirty old alcohol in the boat because i am scaredy cat of propane in a boat.

As you can read, there are safety precautions built into my unit. This also demonstrates that when turned off, there will not be gas fumes building up. I also never leave the canister attached when not cookin, and, where the canister is located, no discharges from it will enter the boat. There is always some sort of puff of gas that will escape unburned at the stove, but I don’t see it of any consequence.

BOAT wrote: ↑Thu Mar 05, 2020 3:25 pm Well, if they make the bilge go boom then I can imagine why there are none available to buy anymore! Maybe they are just too dangerous to sell.

Have you tried a Coleman stove?

You win... where is the white flag emoji?

I'm getting the Coleman one - great for picnics

Where exactly is the bilge on ? Seems like it's got such a flat bottom fumes would be travelling all over the place back and forth.

Looks like propane and ethyl alcohol have almost the same molecular weight. Though propane is stored under pressure as a liquid, and alcohol is stored as a liquid under no pressure other than atmospheric.

I’ll stick with my propane grill in the stern, and my butane stove for the galley. Even though butane has a higher molecular weight than any of those.

I do store the canisters in the cockpit with the gasoline tanks, though.

Jimmyt wrote: ↑Thu Mar 05, 2020 2:59 pm. Close the control gate when it's not in use and put the gasket in place per the manufacturer instructions when you're not using it. Don't call the manufacturer. You will be fine.

THIS ^^

And open a hatch and vent fumes.

I have a Butane stove. Same concerns. I NEVER use it without the forward hatch and open ventilation.

Propane grill off the stern with lots of open air. Same thing. Only use with a breeze to vent.

Honestly, Alcholol stoves seem to be the safest bet. Have you ever lit those fumes? Yea they ignite, but burn "cool" and don't "explode" Fill a container with them and light it. See what happens. You'll get a woof of flame and then it goes out.

Our boats don't really have deep bilges to house fumes. But nevertheless, keeping forward hatch and a breeze through the cabin is a good idea. Don't let any fumes concentrate low.