Fire

More info will follow soon. Phil hopes to install and test the replacements on Thursday / Friday. We need to spend Saturday cleaning up the engine compartment before we dare fire up the engine and check we're charging. Hopefully Phil will find out why we had the problem.

We had been running the (quite old) fridge for 36 hours on battery. It's the most power hungry item on the boat, and I think that duration was only possible due to the excellent winds that kept the wind generator producing power. One mile out of the river the Autopilot told me the domestic battery power was low, (3 x domestic batteries + 1 x engine start), which is why we were motorsailing.
 
Looking at the switch / VSR and the lack of downstream damage to the cables I would suspect the switch went HR and overheated. I'm guessing you either had a switch in the negative or managed to disconnect the battery to save the day. Wouldn't have liked to have tried to turn that when it was hot.

I often wondered why they put switches in the negative, guess this is the reason is it gives you two independent points of disconnection.

Now I am going to be controversial here and declare that I would never have a VSR on my boat, I favour the use of low loss diodes as they fail safe i.e. disconnected.
 
davidwf said:
Looking at the switch / VSR and the lack of downstream damage to the cables I would suspect the switch went HR and overheated. I'm guessing you either had a switch in the negative or managed to disconnect the battery to save the day. Wouldn't have liked to have tried to turn that when it was hot.

I often wondered why they put switches in the negative, guess this is the reason is it gives you two independent points of disconnection.

Now I am going to be controversial here and declare that I would never have a VSR on my boat, I favour the use of low loss diodes as they fail safe i.e. disconnected.
Click to expand...

my boat was originally wired with just the neg switched & a simple relay to bring in the domestic bank.
i now have retained the neg isolator added a 1,2 both & a Victron VSR.
both isolators are accessible outside the engine compartment
 
When we board Santana we always unlock four out of five padlocks with the same key - the cockpit lockers and the companionway hatch. The fifth in the set, securing the quick release for the pushpit mounted liferaft, is usually left locked unless we're going on a longer passage, e.g. across the Thames estuary or across the North Sea.

The keys hangs by the chart table, with the padlocks. Had our fire not been successfully fought but taken hold instead, we would have been unable to reach the key, and abandoned ship in lifejackets, but into the water. Not a problem in the Deben entrance with people close around, but I would have been pretty cross (and felt pretty stupid) to have been bobbing up and down in the sea even a mile off Felixstowe whilst watching the liferaft burn with the boat. Worse still half way down the Wallet or half way to Southwold.

It will always be unlocked before leaving the river in future.

First signs are that failure of the domestic master switch probably caused the fire. All joints and connections were satisfactory, but contacts within the switch are heavily pitted - possibly the result of arcing and thus overheating. The switch casing has proved itself to be flammable - Phil set light to it pretty easily. That said, it's certainly not conclusive at present, and when Phil's tests all the circuits aboard he may find a completely different cause.
 
Barbican Bill said:
When we board Santana we always unlock four out of five padlocks with the same key - the cockpit lockers and the companionway hatch. The fifth in the set, securing the quick release for the pushpit mounted liferaft, is usually left locked unless we're going on a longer passage, e.g. across the Thames estuary or across the North Sea.

The keys hangs by the chart table, with the padlocks. Had our fire not been successfully fought but taken hold instead, we would have been unable to reach the key, and abandoned ship in lifejackets, but into the water. Not a problem in the Deben entrance with people close around, but I would have been pretty cross (and felt pretty stupid) to have been bobbing up and down in the sea even a mile off Felixstowe whilst watching the liferaft burn with the boat. Worse still half way down the Wallet or half way to Southwold.

It will always be unlocked before leaving the river in future.

First signs are that failure of the domestic master switch probably caused the fire. All joints and connections were satisfactory, but contacts within the switch are heavily pitted - possibly the result of arcing and thus overheating. The switch casing has proved itself to be flammable - Phil set light to it pretty easily. That said, it's certainly not conclusive at present, and when Phil's tests all the circuits aboard he may find a completely different cause.
Click to expand...

what make was the switch
 
Bill,
I use a small carabiner hook on a wire lanyard attached to the liferaft frame. I put the liferaft lock key on the ignition key floating keyring to remind me when I start the engine.
Actually I have not locked my liferaft on the frame for the last 3 seasons, until it gets into the yard in winter. Seems like a large price for a small error of memory if the worst comes to it.
 
FullCircle said:
Bill,
I use a small carabiner hook on a wire lanyard attached to the liferaft frame. I put the liferaft lock key on the ignition key floating keyring to remind me when I start the engine.
Actually I have not locked my liferaft on the frame for the last 3 seasons, until it gets into the yard in winter. Seems like a large price for a small error of memory if the worst comes to it.
Click to expand...

Jim, I also use a small carabiner (permanently attached to frame by a lanyard) to secure the liferaft when it's unlocked. No reminder to unlock is necessary - that's why all the padlocks have the same key. I never forget to unlock the cockpit lockers! I just need to change my routine to unlock all five locks rather than just four. As someone who wears a lifejacket and believes firmly in "useless unless worn", it's come as a rather startling revelation to realise how crass I was to deliberately leave the liferaft locked when inshore and the key the other side of the most likely sources of fire.
 
Good news - for us at least.

Phil Munslow finished working his magic today fitting new elastic-trickery switches etc., following our day aboard yesterday cleaning up the dry powder. It all works again, and the air isn't full of powder in the engine compartment, as it was only yesterday. Huge relief. It was nice to motor up river and back recharging the batteries, and looking forward to sailing again next weekend.

A little more investigation is required, but everything is pointing to a domestic battery switch fault, both for causing the fire and for having a flammable casing. I don't intend naming names at this stage without talking to the manufacturer first to get their view. We have replaced the switches with ones from the same manufacturer, but I'm pleased to say that both the design and the materials have changed.

Phil's view is that we were very lucky indeed to spot the fire and put it out before it caught hold. Once again, many thanks to my friends who were crewing. Thanks too to Phil for going above and beyond, and for sorting it out so quickly. (Above and beyond includes a near instant response, taking photos, doing web research, testing switch casing flammability back in his workshop, coming back out to the mooring on a bank holiday Monday, lending batteries, a portable invertor & a small vacuum etc., etc.)
 
Last edited:
That is great news Bill.

Sorry I didn't stop on the way past this afternoon.
Single handed, the main was starting to pull and I didn't want to drop it.

Good to hear you are back sailing again so soon.

Clive
 
I am ordering a replacement for the used extinguisher, and have noted comments made on extinguisher types, here and on a subsequent Fire! thread started on Scuttlebutt

Despite the mess, I now have absolute confidence in dry powder's ability to put out an electrical fire (caught early enough). So, based on my experience last week, I'm replacing it with the same again.

Even SWMBO who spend much of yesterday wearing a breathing mask and clearing up in a space too confined for my bulk is in agreement!
 
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