The danger of fire

[a64pilot]

Originally Posted by Cheechako

Although I have been laxsidaisical (sp?) about having them, it seems a Halon in the engine room is a very important safety item to have, that many don't think about..

I have one and of course with everything they have limitations as well. I have a halon bottle in the Lazarette compt., and another in the compartment directly behind the electrical panel as well as the engine , they all fire when a fuse overheats and melts, just like a sprinkler system in a building. PO or IP installed I don't know which, but I was impressed when I found one behind the breaker panel, that is a good idea I think.
Ideally you would treat it like an aircraft engine fire, once either the flame detection system or overheat system is activated that sounds the alarm and the fire pull handle is illuminated, pull the handle and fuel is immediately shut off, all vents to engine compt are closed and fire bottle squibs are armed, you can then discharge the bottles or not, but without shutting down the engine and closing off the vents your Halon is likely to go right the exhaust.
The Viking motor yacht I helped in the Dry Tortugas was set up just like the aircraft system, he couldn't move as his system had detected an overheated battery correctly and had shut off fuel and air to the engine room, so we had to disable the battery temp sensor so he could get home.


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[SteveInMD]

A firefighter friend of mine tells me - if one fire extinguisher doesn't do the job, get out while you still can.

[barnakiel]

The only time I had fire on a boat, it was on the engine AND the automatic system, surprisingly, did not kick in (a FireBoy). I thought about that A LOT and found it was because the temperature did not get high enough.

Now the problem can be that it is too late once the temperature is "enough" and an automated system deploys. Maybe the fire is beyond control by then.

So probably if you have an automated system, you may want to make sure it can be easily deployed manually, without opening the room.

b.

[Kenomac]

We have a Yanmar 4JH3-HTE, almost the same engine. Thanks for the post. We had a fire, although very small on our engine two years ago involving the starter motor, it was electrical. I'm glad most everything worked out for the couple involved.

I'm guessing that the Mexican healthcare system isn't as good as so many living down there seem to believe. ;-/

Thanks for the fire extinguisher information, I'll remember how to extinguish the turbo with water.

[Tayana42]

This thread has got me thinking. (That is normally a dangerous or expensive thing but this time I guess it makes sense.)

The spaces I'm most concerned about a fire starting are 1. the engine box under the saloon seat and galley counter, 2. battery and charger space under the quarter berth, 3. circuit breaker panel. Three fire ports would be easy to install. I like the transparent ones that allow you to visually detect what's going on without opening and oxygenating the area.

In order to cut a 2" hole through the side of the engine compartment which is beautiful teak faced plywood I also have to cut a 2" hole through the soundproofing panel which is about an inch thick. I'm a little concerned about increasing the noise level below. Right now the sound of my Yanmar 4JHE is very quiet and I'd like to keep it that way. Thoughts?


S/V B'Shert

[Lepke]

I've been in 2 ship fires and 1 boat fire. The trick is to quickly knock down the fire before other things get involved like paint, wire insulation, or structure. I went to navy fire fighting school 3 times in 4 years. The navy takes ship fires seriously. We used water with special nozzles to put out oil fires. But it takes 2 hose teams or more and enough water to sink most yachts.
I think most boat fires are from corroded wire connections or overloaded wiring. I check my wiring with a infrared thermometer ever couple years when the circuit is carrying a load.

[JPA Cate]

Tayana 42,

Just mho, but I think I'd put up with the fire port for the peace of mind. Imagine what you'd be thinking clinging to two fenders in the middle of the Sea of Cortez, what a desolate terror. Sure you'd come to grips with it, but...... Anyhow, to me, anyway, cruising is to be considered from a practical point of view. Our boat is all timber, except for the epoxy and glass in and out, so below is fitted out in a combination of eye pleasing timbers, and I wouldn't really want to destroy its beauty. However, I think there is a relatively inconspicuous place on the exterior of the box that would do. Good deal, eh? Yes, it might be noisier, but would you rather put up with the noise or go float-about? Maybe talk about it with your good lady?

I really like Lepke's idea of using the optical thermometer to check the potential hot spots. Once you establish a base line, you'd be able to notice immediately any heat which is unusual for your boat.

[Kenomac]

Here's what I learned from the story, one person fights the fire while the second sends out the mayday, readies the dinghy, liferaft and ditchbag.

[Tayana42]

Anne, as usual, thanks for your wise thoughts.


S/V B'Shert

[Tayana42]

Ken, that seems like a good plan in any fire situation on board. Given that's our boats are make of combustible petrochemicals getting ready for immediate evacuation makes sense.


S/V B'Shert

[Paul L]

I really doubt you will hear any noise difference when you add a fire port. They are small and the sound will still be muffled as it bounces down the tube formed by the sound proofing hole. I sure can't tell the difference on my Yanmar.

[Tayana42]

Thanks Paul. Good to know.


S/V B'Shert

[Cottontop]

So does this make sense for a sequence of events in the engine room:

1. Alarm (noting Kenomac's concern about the timeliness of an alarm).
2. Shut down engine and fuel supply.
3. Halon (or its successor), to snuff the flames, quickly followed by
4. Water, to cool things off.

[poiu]

A fire will start slowly and its progression becomes geometrically faster with time. First there will be heat, then invisible smoke (that can nevertheless be detected by good smoke detectors), then visible smoke and then fire. Catching it early has to be key.

In an engine room with the engine sucking away most fumes I imagine a smoke detector won't work as well as it will behind an electrical panel. Maybe there is a better way. There are flame detectors, which could save a minute or two compared to the thermal builb devices. I don't know if there are heat anomaly detectors. Should be possible.

The system also has to be loud enough to be heard whilst sleeping or if on deck in a gale. I'm going to think about a central control with remote sounders.

[poiu]

Originally Posted by Cottontop

So does this make sense for a sequence of events in the engine room:

1. Alarm (noting Kenomac's concern about the timeliness of an alarm).
2. Shut down engine and fuel supply.
3. Halon (or its successor), to snuff the flames, quickly followed by
4. Water, to cool things off.

Sounds right. You can't go in though as that will release the extinguishant and let O2 in. Plus you may suffocate. So a hole for a hose in the right place might be best. Or sprinklers.