Engine Room Extinguishers

[Chenega]

Could someone suggest the type and size of an extinguisher for use in an extinguisher port on our Corbin 39. I assume oxygen displacing system such as Halon (are they still available?). Looking for suggestions as we outfit for long term cruising.
-thanks

[billknny]

Halon extinguishers are available, and are a good choice for engine room work since they don't make a god-awful mess. I don't know if any are USCG approved, so it might not "count" on your inventory.

Be sure you get the right size, and can shut off any ventilation ports into the engine room.

You want to be sure you rig it so you can't use it in the cabin, breathing would be--unproductive!

[callistov42]

I have the Fireboy automatic in my engine room. West Marine sells them (not inexpensive) but seems more than worth the cost. They are Marine rated and meet CG requirements.

[a64pilot]

Halon is still out there in the US, but it ain’t cheap. It comes usually as two forms or as a mix. They are 1211 and 1301 I believe.
I think and am not sure that 1211 is a gas, and 1301 a liquid. It’s the only agent the FAA allows on Commercial aircraft, I think. 1211 for flooding an enclosure and 1301 when you want a wetting agent
Halon unless in ridiculously high concentrations won’t interfere with you breathing, but of course displace all the air and you will suffocate, being able to breathe after it puts out the fire is why the US Army uses it in armored vehicles.
I have several Halon bottles in my boat, it came with three automatics, one in the engine room, one in the Lazarette, and one in the electrical cabinet behind the fuse panel. The electrical one is I think smart and one I wouldn’t have thought of. I believe most fires are electrical?

I also have a larger Halotron bottle, it’s a Halon replacement, won’t make a mess, isn’t bad for the environment, not nearly as expensive, but takes twice as much for the same effectiveness of Halon.
My handheld 2.5 lb bottles are a mix of 1211 and 1301, which you often find in aircraft, they are actually aircraft fire bottles, not that that matters, but you can buy them at Aircraftspruce.com

What is very, very important in an engine room fire is to shut down the engine first, or it may pump all the Halon right out its exhaust, it will shut down of course, but as it rolls down its pumping agent out of the room.
With an aircraft what happens usually if you pull the fire pull handle is air is first shut down from around the engine, the fuel valve motors shut and the fire bottle armed.
Larger expensive power boats that I have seen also slam the big air louvers shut and shut down the motor, you May can’t do that but at least shut down the motor before firing the bottle.

I have one auto one in the engine room that I honestly don’t think would do much more than kill the engine, but I also have a frangible “window” in the side of the enclosure that I can poke a fire extinguisher hose through to discharge it, that’s what my Halotron bottle is for.

Be prepared for many to decry you for even considering Halon, I believe however if I discharge a 2.5 lb bottle of halon and the boat doesn’t burn to the waterline that there is less environmental damage than if it does burn to the waterline.

Do not be afraid to use it in the cabin, or use the Halotron although I don’t know about breathing Halotron, but if you have ever set off a dry chemical fire extinguisher in an enclosed space two things happen immediately, first you can’t breathe, it won’t kill you, but it is extremely irritating to mucus membranes, and because of that, you won’t be able to see either, your firefight is over.

This may be of some interest to read.

http://sandpyper.blogspot.com/

Last thought, don’t downplay plain ole water, having a hose available connected to your water tank">fresh water tank or wash down system may have saved their boat, maybe

[Hans2]

It's been my understanding that Halon systems were no longer legal for shipboard installations since the early 2000's.

When I installed an engine room extinguisher in 2015, I had to calculate the cubic feet of air in my engine room and bought the appropriately-sized unit made by SeaFire.

Remember your engine is an air pump itself, so if the extinguisher deploys while it's running the engine will pump a not-insignificant amount of suppressant right out the exhaust before you shut it off or it dies. With that in mind, buying one size suppressor larger than necessary may be a good idea.

*I see a64pilot has a far more comprehensive understanding then I do, great stuff in his post above.

[Chenega]

Thanks all for the information and ideas to consider