Avoiding unattended boat fires

[Tessellate]

Recently a motorboat at our marina caught fire in the middle of the night with 40 knot gusts, sunk and also burned the hull of a sailboat next to it. Very sad. Tragic boat fires seem to happen way more often than they should, given advancements in our understanding of fire safety.

It got me thinking - what are the most common causes of unattended boat fires? By unattended I mean no one's at the boat, nothing has been touched on it in several hours at least, and I'm assuming no direct human action caused it like falling fireworks or arson.

I found this Boat US article and they say the most common cause is electrical - not surprising. Boat Fires - Seaworthy Magazine - BoatUS More specifically, the most common electrical causes are: chafe in wires causing a short, or AC heaters left running that either set something on fire with direct contact, or cause an overheating fire in wiring due to resistance/corrosion.

But I'm still wondering - what causes boat fires to happen in the middle of the night when the boat is pretty much not moving at all? If it's wire chafe, wouldn't it already have caught fire while at sea where there's much more movement and more circuits turned on? And if it's an AC heater, what changed in the middle of the night to cause the fire then rather than the fire happening hours or days ago?

Obviously the shorepower cord could be yanked by wind and improperly set docking lines. Would a practice of turning off all appliances and circuit breakers before leaving the boat prevent most unattended boat fires? No amperage flowing = fewer chances for dead shorts / resistance heating?

Lastly, is there anything you can do to avoid your *neighbor's boat* setting you on fire? That's really bum luck. Don't park next to ill-maintained boats I guess would be a start? But even nice-looking boats catch fire sometimes.

[barnakiel]

I think very very many fires start in the electric box.

I too had a fire in the engine room of the boat I managed (Perkins Sabre - the engine loom).

Our own boat is disconnected from the shore power at night and when we are away. And anchored out we switch everything off at the battery switch when we go ashore. Only the bilge pump is hardwired (with its own fuse).

So my take is: have quality electric installation 'overfused' and switch stuff off when not needed.

What else could be done?

Cheers,
b.

[zeehag]

too many fail to twist lock their cords, which causes increased resistence from the fail connection.
this heats up the cord and box and burns happen. please twist lock your cords both at boat and dock box connections.
yes it makes a difference--use a surge protector with warnings for reversed polarity and ground fault interrupt and see for yourself. i know when my cord has been removed and replaced by the lights on my surge protectors--one has red light, the other green. improperly installed the the lights will not be on. when i see this--i go to my dock box and twist the lock so connection is restored properly. then magically the green lights are back on letting me know the connection is made.
the plug becomes very HOT when the connection is fail. ask me how i know, ot how i made the burning smell go away
you would be surprised at the number of folks who do not correctly use the shore power connections.

[senormechanico]

A thing I personally saw while working at a yacht maintenance company 20 years ago in Seattle made the hair on the back of my neck stand up.

It was a beautiful 48 foot Tollycraft 50 amp electrical service panel which had all electrical baseboard heating connected to it as well as a couple of portable electrical heaters.
Done properly not so bad, but this one was not.
The hot side buss bars feeding the breakers were insulated with some kind of rubber light green stuff and had 1/4" spade female connectors coming out of them.
These had to be plugged onto the breakers all at the same time as they were rigid with the buss bar.
Anybody on a boat with experience with 1/4" connectors will tell you they loosen over time, and this boat was no different.
Once or twice, he would call us to make something work again and it was usually those quarter inch connectors which were loose.
There were several places in that box which showed signs of overheating, turning brown, wiring insulation going hard and stiff, etc.
All the guys I worked with said they wouldn't be surprised if the boat caught fire someday.

We pleaded with the owner to let us rewire it properly or get a professional to do it, but no joy and this boat was owned by the owner of the marina!

I don't know the outcome, because I quit my job and moved to Whidbey Island.

[Smokeys Kitchen]

I haven't really researched it, but I think the most common is electrical fires; especially when unattended. It seems to me that the thing that would be changing is the load on the wires - due to a thermostat kicking off a heater or some other load.

I have a neighbor in the marina here, 20 year Navy vet - electrician. He and the wife left their boat for a short overnight visit and their daughter was staying on board. It was very cold this winter and all his heating methods were going. Large power boat with recirculating (?) water heat, electric baseboard and diesel. He called me @ 10 at night saying his daughter told him the power had gone out. His 50 amp breaker had tripped at the dock box - but the enclosed picture tells another part of the story. The photo is the inside of the receptacle on his boat where the shore power cord plugs in. Took me 20 minutes to unplug the cord from the receptacle. This was a very lucky outcome; he changed over to a smart plug the next day. And this boat was much larger than the one that caught fire and sank a week ago.

Experienced boater; knowledgeable electrician. Huge increase in power draw and a bad receptacle. I check mine all the time now.

[Tessellate]

Boat US recommends not using any heaters while the boat is unattended. But this isn't really viable for boats in humid temperate climates that are not hauled in the winter because they're used year-round. Unless you want a bunch of black mold growing. So it seems safe practices around heating are something that's needed.

We manage to heat millions of houses in the US without many of them burning down. It is curious to me that we can't do so on boats, and that an insurance agency is actually recommending people don't use heat. No home insurer would recommend people not heat their houses, because they would be laughed at (not to mention pipes could burst).

Some practices I follow with AC heaters are: always use AC heaters designed for marine use, replace the heater regularly (yearly?), keep it far from any combustables and make sure there are no items hanging above it that could fall on it.

[wsmac]

This is why I'm taking my time, combing through both the AC and DC systems to make sure these things are safe!

Also, when I walk down my dock (my slip is at the bitter end.. ), I glance at all the shore power cords stretched out from the power poles.
I like to take the ones dipping down into the water... out!
Pulled one out for the large, nice-looking Cat at the very end of the dock, that had enough loops into the water it was starting to make a nice artificial reef!

Hopefully the next time the owner comes out, they'll see all the caked-on stuff on their cord and realize they should be a bit more careful!

Anyway... back to my boat...
Just from going through the DC system... I soon realized one or more people had their hands on this and didn't have a basic understanding of what a safe system looks like! Or how to create an efficient functioning electrical system!

Been snapping plenty of pics of the mess I've been dealing with!
Luckily, I haven't found the same ignorance applied to the AC... but it is time to replace the old shore power cord and I get the feeling the PO didn't care about spending the money on a new cord for some time.

I'm somewhat concerned about walking away from a boat with devices plugged in that are always on and running... heaters, fans, ozone devices...

If it's in great operating condition and the AC system is also... AND... the device is meant to be run 24/7... then yeah... I don't see why there would be a problem except for that once-in-a-while item that left the plant without proper QC.

So to me... making sure any device I plug into my boat isn't one that's just clanking along but 'seems to work okay' or doesn't show any indication it was meant for continuous usage.

There are timers and all manner of circuit interrupters that can be applied between the outlets and the device as well.

All this reminds me to get my new shore power cord today... while I go back to working on dismantling/reorganizing/replacing the DC system.

[CarlF]

Mainesail had a good comment some months ago. It's really a bit risky to leave a boat unattended with the batteries being shore powered charged by the same very high amperage battery charger you might need when the boat is occupied.

Normally the charger would be on float pushing a few amps - but if something goes wrong with the batteries or the charger, you can have 100amps of charge getting pushed into an overheating battery bank for weeks.

I'd never thought about this.

[CarlF]

Looking at those pictures, you might also worry about another risk of electricity other than fire - stray-current corrosion. You could come back to your boat to find it sank because galvanic corrosion dissolved a seacock. Electric leaks from wet DC bilge pump wires are a common cause.

Some examples
http://www.qualitymarineservices.net...corrosion.html

[witzgall]

Amp + Resistance (corrosion, wear) = Heat,leads to melting insuation, overheated wires = fire.

The hubbel connector design used in shorepower connectors was created in the 1930s. In the case of the 30a connector, it was originally designed as a 20a continuous connector (and flawed at that). When pressed into marine service, it was specified as a 30a INTERMITTENT connector. Sometime later, the intermittent label was dropped. The connector has a very small surface area. If you are running anything approaching 20a on a regular (meaning more than a few hours) basis, it is insufficient. If you are using electric heat on a boat, it is not a matter of if, but when it will fail.

To learn more, check out main sails pictorial. Shore Power Cords - SmartPlug vs. 1938 Photo Gallery by Compass Marine How To at pbase.com



The ONLY suitable replacement on the market, IMHO, is the Smartplug. If I were king, I would require it at all marina owners. If I was a marina owner, I would require it for all live aboards, or winter (heater) users. I would also work with Smartplug to get them discounts.

Chris

[Lepke]

Many owners, willy nilly, add to existing circuits. Often w/o fuses. I use a heat reading gun and routinely check my connections and breakers for excess heat. It's the first thing I do with a new-to-me boat. I turn everything on and start at the breaker panel.
Many boats, even new ones don't have heavy enough wiring for the many of the things we use. Especially electric heaters. Over heated wiring can ignite insulation and slowly build a fire within a wall or other enclosed space.

[wsmac]

Originally Posted by CarlF

Looking at those pictures, you might also worry about another risk of electricity other than fire - stray-current corrosion. You could come back to your boat to find it sank because galvanic corrosion dissolved a seacock. Electric leaks from wet DC bilge pump wires are a common cause.

Some examples
http://www.qualitymarineservices.net...corrosion.html

If you are referencing my pics... OH YEAH!
I plan on installing a glavanic isolator, checking all grounding points I can access on the boat, as well as making all wire splicing - Marine Grade, all connections elsewhere - Marine Grade (what's the best brand of Marine Grade tape to wrap around a couple of wires twisted together? Maybe the PO used the right stuff? hahaha )

That Rat's Nest in the bilge really set off my alarms when I opened it up to see how full the bilge might be and to check the switch and pump back when I was just looking.

One of the times I was on board checking things out pre-sell... the PO flipped on the lights, I lifted the float switch and heard the bilge pump run....
Then a couple weeks later after the PO had installed 2 new RV/MARINE batteries from Costco (Interstate brand)... not only did the electric start on the o/b stop working... but no DC power anymore!

As I mentioned before... the AC checks out, but the shore cord is looking old and a bit dried out in the cover so I'm getting a new one!

Galvanic corrosion is yet another reason I look at other people's shore power cords as I walk down my dock. I'll pull up on the dock any cord I see in the water.
If it's one of the liveaboards on my dock... I'll just mention it to them and see if they pull it out on their own. But the boats that people hardly tend to... I'll do it for them.
It's an issue for anyone else on that dock as well as anyone who wants/needs to dive below a boat... hull cleaners for example.

[barnakiel]

Does it make sense to have an automatic extinguisher behind the el-panel?

Or am I being silly now?

They exist in many engine rooms. Why not where(else) fires are known to start?

b.

[Cadence]

Originally Posted by Tessellate

Recently a motorboat at our marina caught fire in the middle of the night with 40 knot gusts, sunk and also burned the hull of a sailboat next to it. Very sad. Tragic boat fires seem to happen way more often than they should, given advancements in our understanding of fire safety.

It got me thinking - what are the most common causes of unattended boat fires? By unattended I mean no one's at the boat, nothing has been touched on it in several hours at least, and I'm assuming no direct human action caused it like falling fireworks or arson.

I found this Boat US article and they say the most common cause is electrical - not surprising. Boat Fires - Seaworthy Magazine - BoatUS More specifically, the most common electrical causes are: chafe in wires causing a short, or AC heaters left running that either set something on fire with direct contact, or cause an overheating fire in wiring due to resistance/corrosion.

But I'm still wondering - what causes boat fires to happen in the middle of the night when the boat is pretty much not moving at all? If it's wire chafe, wouldn't it already have caught fire while at sea where there's much more movement and more circuits turned on? And if it's an AC heater, what changed in the middle of the night to cause the fire then rather than the fire happening hours or days ago?

Obviously the shorepower cord could be yanked by wind and improperly set docking lines. Would a practice of turning off all appliances and circuit breakers before leaving the boat prevent most unattended boat fires? No amperage flowing = fewer chances for dead shorts / resistance heating?

Lastly, is there anything you can do to avoid your *neighbor's boat* setting you on fire? That's really bum luck. Don't park next to ill-maintained boats I guess would be a start? But even nice-looking boats catch fire sometimes.

Consider the AC heaters, you mentioned being set to come on at a particular temp. and night time temp drops. It wasn't on when they left so no one thought about the combustible left in front of it. Human error?

[ArmyDaveNY]

Originally Posted by witzgall

Amp + Resistance (corrosion, wear) = Heat,leads to melting insuation, overheated wires = fire.

The hubbel connector design used in shorepower connectors was created in the 1930s. In the case of the 30a connector, it was originally designed as a 20a continuous connector (and flawed at that). When pressed into marine service, it was specified as a 30a INTERMITTENT connector. Sometime later, the intermittent label was dropped. The connector has a very small surface area. If you are running anything approaching 20a on a regular (meaning more than a few hours) basis, it is insufficient. If you are using electric heat on a boat, it is not a matter of if, but when it will fail.

To learn more, check out main sails pictorial. Shore Power Cords - SmartPlug vs. 1938 Photo Gallery by Compass Marine How To at pbase.com



The ONLY suitable replacement on the market, IMHO, is the Smartplug. If I were king, I would require it at all marina owners. If I was a marina owner, I would require it for all live aboards, or winter (heater) users. I would also work with Smartplug to get them discounts.

Chris

This is spot on! I sell this stuff and more often than I care to think about people come in with damaged (from over heating and/or fire) shore power connectors. The most common denominator is the corrosion on the tabs inside the connector. As you and others have pointed out, a properly set up AND properly maintained system is critical.

I had an interesting conversation with Marinco and they were quite insistent that the Y connectors were only intended as temporary solutions in cases where a marina doesn't have the correct shore power while one is temporarily staying at it. They were also quite clear that corrosion is a killer and that the shore power was not a plug and forget system.

Too many also never check the dock side of the shore power system. Too often the marina has a bad ground or corrosion in their side of the system.

When I bought my first boat I was all excited about shore power and having "constant" and "permanent" power solutions. Now I rarely leave shore power plugged in and most often don't even use it. Yes, I have it and use it, I just use it as a supplement and not as a primary source of power.