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-   -   Bilge Fire Today - thoughts on cause? (https://www.offshoreonly.com/forums/general-boating-discussion/385624-bilge-fire-today-thoughts-cause.html)

seafordguy 06-14-2025 07:46 PM

Bilge Fire Today - thoughts on cause?
 
Had a scary day today. Bilge fire, clearly electrical.
burned up wires running from alternator, and lots of the other ancillary wiring in the vicinity like oil pressure, water temp alarm, main breaker which is rear mounted on my boat, etc…….

any thoughts on cause from the group? I honestly think it started at the alternator connection but not sure why necessarily.

kind of a mess because all those spiral wire sheaths burned up, I think one or two of the bilge hoses got melted, etc…..

scary that the halon didn’t activate and I had to put it out with a hand held fire extinguisher…….

Sydwayz 06-14-2025 08:01 PM

Super scary! Glad you are alright. Still at the dock? Or out on the water?

seafordguy 06-14-2025 08:11 PM


Originally Posted by Sydwayz (Post 4928340)
Super scary! Glad you are alright. Still at the dock? Or out on the water?

Out on the water, but luckily close to home. Need to figure out tomorrow what this is going to entail. Lots of different Mercruiser wiring harnesses so need to figure out what I need to buy for an old school carbed V8

Rookie 06-14-2025 08:15 PM

Do you have any -AN stainless braided fuel or oil lines? I have seen those rub and arc across some hot wires. They will get red hot.

seafordguy 06-14-2025 08:31 PM


Originally Posted by Rookie (Post 4928344)
Do you have any -AN stainless braided fuel or oil lines? I have seen those rub and arc across some hot wires. They will get red hot.

Interesting. Definitely have those running from my front mounted oil coolers along that side of the motor up to the filter housing. I’m going to have to look at that tomorrow…..

bajaman 06-15-2025 07:33 AM

Unlucky and lucky at the same time! I hope you get the root cause figured out and repaired soon.

Tartilla 06-15-2025 12:50 PM

Pics would help here.

Poor connections on wires can get hot trying to pass the Amps. Alternator cna put out reasonable power...what were you run ing for elec at the time?

Shorts from abraded wiring should have popped fuses.

Glad everything turned out ok.

Good reminder that wiring maintenance is important, if only to help rule out fire ignition sources. Not to say you weren't up on it.

seafordguy 06-15-2025 06:38 PM


Originally Posted by Tartilla (Post 4928400)
Pics would help here.

Poor connections on wires can get hot trying to pass the Amps. Alternator cna put out reasonable power...what were you run ing for elec at the time?

Shorts from abraded wiring should have popped fuses.

Glad everything turned out ok.

Good reminder that wiring maintenance is important, if only to help rule out fire ignition sources. Not to say you weren't up on it.

I didn’t get to check it out today due to the weather. I’ll report back tomorrow, wires to alternator were completely disintegrated. I I’m going to trace it TOMORROW. Hopefully I can figure it out. Any chance the alternator could have had an odd failure and caused the issue. It’s a well kept boat - never a drop of water in the bilge, kept indoors 9-10 months a year. Lift kept the rest of the time.

Hardin has a couple pigtails and I’m hoping I can get away with replacing from the main harness 9-pin down and possibly the breaker and starter solenoid since they got some damage/heat. I’ll know more tomorrow when I can pull the exhaust and get around back a bit better. Ugh…..


36Tango 06-15-2025 07:09 PM

I cannot lend anything to help with the issue, but damn you got lucky as lots of bad things could have happened. I am glad that you had a fire extinguisher handy. It will be interesting to see what you are able to figure out.

seafordguy 06-16-2025 05:55 AM


Originally Posted by 36Tango (Post 4928429)
I cannot lend anything to help with the issue, but damn you got lucky as lots of bad things could have happened. I am glad that you had a fire extinguisher handy. It will be interesting to see what you are able to figure out.

Yes, very unpleasant feeling standing on 200 gallons of fuel watching a flame burning in your bilge.

You kind of react in the moment because I certainly wasn’t expecting that, but definitely some things I would do differently if it ever happens again.


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