Propane Placement Poses A Predicament

[sdowney717]

Nemo55, the automatic bilge pump better not spark, or the automatic switch.

All the ones I have or have seen are all ignition protected!

[terminalcitygrl]

Knock it off please. And I don't mean the propane tank.

[micah719]

Hmmm, a possible idea for a fail-deadly device when a Honduran Freelance Customs Agent has bailed you up at pistolpoint.

[YOUTUBE VIDEO]

Yachting Monthly's Crash Test Boat - Explosion! - YouTube

[/YOUTUBE VIDEO]

[micah719]

Solved the rotting deck-core problem....

[dirkdig]

Bit of resin and some mat offcuts it will come up ok

[Coachbolt61]

Haven't read all the responses so apologies up front. An idea I had for my boat. Nearly every boat I have seen has stern seats either outboard of the transom or inboard of transom. Why not incorporate the bottle underneath one of the seats? Seats would have to be either slightly wider (more butt room) or extended aft under the rail. Front could be either slats or solid with the back open. If there is a kaboom (as Wile E. Coyote would say), the blast would go back or up. People's thoughts? Cheers. Coach bolt.

[Mr B]

My Gemini has the gas bottles under the seat inside the transom, inside the cock pit,
It has a hole between the bottles that lets any propane escape straight out underneath the bottles into the open air under the boat,
It also has propane gas detectors installed inside the locker, which also has a fail safe on it,

I also check the connection with a soapy wash after, when ever I change the bottles over,

I Googled Propane explosions on yachts, A 63 foot schooner got blown clean out of the water, Chebucto, 2007
also a 38 foot Mono in Seattle got blown apart and took the two boats out on both sides,
But it is more common for petrol boats to explode than propane, due to regulations regarding Propane storage,

But if you put propane in a bilge, You wont sleep at night,

[sdowney717]

Since propane is heavier than air and sinks, say it fills a bowl, wont it eventually dissipate by simple diffusion and slight air currents?

If your cookstove was left on not burning or it leaked into the cabin, how long would it remain at high enough level to explode. Week, month etc...

I know there are lots of variables involved.

[Sailmonkey]

Originally Posted by sdowney717

Since propane is heavier than air and sinks, say it fills a bowl, wont it eventually dissipate by simple diffusion and slight air currents?

If your cookstove was left on not burning or it leaked into the cabin, how long would it remain at high enough level to explode. Week, month etc...

I know there are lots of variables involved.

With no air movement the explosive mixture will stay indefinitely. Air movement is the key, and that depends on the boat.

[Mr B]

I lived in a 28 foot caravan here while building my house,
my stove used to go out while cooking, but the gas stayed on, I was on the phone and the stove went out,

No problem, I just leaned over and lit the thing again, Stupidly, as I did, I realized what I was doing and threw myself backwards as the lighter flamed,
The explosion took the hair off my arm, my right eyebrow, the right side of my hair and mustache, and singed my shirt, I was bloody lucky,

I fixed it after that one, It was out for approximately 2 minutes,

say 5 minutes and it would have enough force to level the caravan as it would have filled all the cabinets,

Its really not stuff you play with, I treat it with the utmost respect, and I make sure all my connections are perfectly tite,

[s/vfootloose]

I remember back in the late 70's early 80's people would build a box a the aft end of the cockpit for propane expecting any fumes to go out thru the drains. The nickname for them was ejector seats.

[sdowney717]

I was thinking if you had a propane detector to turn on a blower and the detector failed, your not protected.
How about in addition to a detector you have the blower on a timer. So maybe twice or three times a day it comes on for 5 minutes. This would be better than nothing as a backup. A blower is ignition protected, it wont explode the propane.

[zeehag]

ejector seating is excellent for crew that doesnt pull their weight....or wannabe pirates, off-key musicians...many uses..

[videobear]

Originally Posted by sdowney717

I was thinking if you had a propane detector to turn on a blower and the detector failed, your not protected.
How about in addition to a detector you have the blower on a timer. So maybe twice or three times a day it comes on for 5 minutes. This would be better than nothing as a backup. A blower is ignition protected, it wont explode the propane.

That's not a bad idea, but a properly designed propane locker should already have double redundancy...externally vented with the vent at the low point of the locker is your first and best protection...automatic, all the time, by design. But if the vent gets blocked, you also have a detector/alarm. Note that three things have to fail: 1) The tank or connection must leak, 2) the vent must be plugged, and 3) the detector or alarm circuit must break. Oh, and a fourth...there must be an ignition source.

I'm not sure that more redundancy would be worth the bother. (I'm a rocket scientist, not a marine engineer...in my business, we WOULD have the additional level of redundancy. And a titanium tank. But a boat is not a space mission.)

[sdowney717]

1) The tank or connection must leak,
or operator stupidity, operator under the influence, drugs, or drunk, regulator failure, diaphragm leaking, hose worn out or someone leaves it on not lit

2) the vent must be plugged
leaves, dirt, debris, insect animal plugs hole-tube, spiders, mud dauber wasps etc...

3) the detector or alarm circuit must break.
well all electric stuff fails to work, gets old, corroded, wet, blown fuse, who forgets to test and see if it even is working, detector gets many years, old, looses sensitivity. I have see lots of non working electrical items that people dont interact with at all.

4) there must be an ignition source.
Someone plugs in something = spark, someone unplugs something = spark.
A smoker light cigarette, someone lights stove, someone burns a match in bathroom, someone throws a switch, someone plugs in something and blows breaker which sparks, someone uses a powertool which has sparks. etc...

I can see it coming together like a perfect storm of events. How often do people check the propane lockers to see if they are plugged by pouring in water? Ever, or Never?

I think most people could smell the gas, but some people cant smell anything, loose sense of smell. Having nose failure, sick, cold, or something else.