Engine Compartment Fire Extinguisher

[PeterPalmieri]

Hey guys,

If you didn't see my thread from a few days ago I am a new B31 owner, just took delivery on Saturday.

One of the first things I need to do is replace the fixed clean agent engine compartment fire extinguishers. During the survey it was point out that they were not inspected and tagged. The previous owner brought them to a extinguisher company that said that they are Halon and due to the fact that they have rust on them they should be replaced.

I am hoping you guys could recommend a replacement, not sure of the CU Ft coverage I need for this and if my best bet is to get the Fireboy Zintex MA2 from Westmarine. Is that the preferred brand and is West Marine the best place to get them or can I find a better deal/quality somewhere else.

Thank you in advance for any advice...

Pete

[CaptPatrick]

The Fireboy systems are pretty much the benchmark systems. Do a Google search for alternative sources to Worst Marine...

The minimum volume system you need is the MA2-075-FE241 @ 75 cu ft. Max would probably be the MA2-150-FE241 @ 150 cu ft. This is PER engine space. See Fireboy Chart

To be effective, you need to have an automatic shut down wired such that it shuts down BOTH engines simultaneously, even though only one unit trips. Otherwise your fire surpressant will be quickly ingested into the running engine(s) and shot out though the exhaust.

Also check in to the Fireboy CG2 Series Fire Extinguisher at Consumer Marine

[PeterPalmieri]

I have to have some electrical work done on the boat over the winter and will address the automatic shut down at that time. Will that effect how I go about choosing a particular model of extinguisher or does the engine shut down work independently of the extinguishers?

I guess my question is should I buy the shutdown system with the extinguishers and have a qualified technician do all the work or can I mount the extinuishers now and adress the auto shutdown in the months to come?

Pete

[CaptPatrick]

While the likelihood of an engine compartment fire are relatively low on a well maintained boat, you'd probably be OK without the shut down system for a while. But, IF you did encounter a fire and the engines are running, you may not have adequate protection without the shut down system in place...

The shut down system is triggered by the extinguisher(s) going off. The B31 engine spaces are only isolated visually when closed & viewed from the cockpit. Since the two are well connected from below deck level, and if you have dedicated shut downs for each extinguisher, either engine, left running, will possibly exhaust the suppressant before the fire is extinguished.

You'd want either extinguisher to independently shut down both engines. Could you do the necessary wiring? Probably, but you'd want to at least consult a Fireboy Tech for the proper procedure.

[PeterPalmieri]

It looks like the only difference in the MA2 vs. CG2 is the manual option. I don't understand how and why I would use manual operation. Can someone explain?

In any case I will pick up one of these two and worry about the auto shut off as I address other electrical issues over the winter.

[CaptPatrick]

I don't understand how and why I would use manual operation.

Manual only means that you'd need to physically see or personally detect a fire and then shut the engines down manually. By that time your surpressant has probably already gone through the exhaust...

A manual system, means also that you can manually trigger the bottle to discharge even in the absence of a fire triggering the bottle. Fine for cabin spaces or anywhere an engine isn't acting like a shop vac to deplete the suppressant.

You want a system that is auto shut down and triggered by the release of either extinguisher. You are completely outside of the equation loop.

Fire ignites --- bottle goes off --- engines shut down --- suppressant lingers until engine box is lifted. The bottle is triggered by either an expanding fluid in a glass fuse or by a low melting point metal fuse. The fuse stoppers up the discharge valve of the bottle until it fails. The automatic shutdown switch is also triggered by the fuse.

[PeterPalmieri]

Thank you Captain for that lengthy response. With all the "need" to do on the boat I don't see me adding a manual switch and a fire port anytime soon. I am already in touch with an ABYC electrician who is going to do some work for me. I will discuss adding the automatic engine shut off with him when we meet at the boat over the weekend.

I am going to get the CG2 and have the automatic shutdown installed...

Thank you very much...

Pete