Fires in boats : electrical or engine-related ?

[carioca1232001]

This afternoon I was met by some friends at my Yacht Club who said:



' Keep on the lookout and touch wood ..... witches (devils) seem to be on the loose this week ...... ....there have been two serious fires this week on members´boats ..........one boat was gutted as it entered the Bay in Angra (70 nautical miles south of Rio) and its occupants just about had time to radio for help and abandon ship before it sank ..... lucky for them that this did not happen while they were crusing off-shore, prior to entering the Bay........the other boat´s captain was moving away from the Club´s dock and steering (at low revs) towards the Club´s refuelling station some 50 metres away, when on noting smoke coming out of the engine compartment louver, swiftly moved towards an empty space of nearby dock, when the Club´s staff were able to flood the louver with CO2....captain was smart too, not to open the engine hatches.......kept his cool, all through the ordeal......'

Could these be electrical fires or engine-related ? One boat was travelling at cruising speed while the other was at docking speed

What practical steps can be taken to mitigate the occurrence of fires on pleasure boats, in manner of the boat´s electrical system, the layout of the engine space and the fuel tanks ?

Should a fire start on board, how may it be put out effectively ? Are automatic fire-extinguishing systems, or alternatively manually-operated extinguisher systems, part and parcel of good seamanship ?

I am requesting that the seasoned sailors of WBF share their knowledge and experience in this matter with novices like myself.

Frankly, the thought of a fire on board while cruising, has struck home, loud and clear, as I know both the parties whose boats were so afflicted.

[carioca1232001]

Bump !

[Gary E]

I dont have any experience with puting out a onboard fire, and since I think it's unlikely that I'll be looking at the area if and when one starts, I believe in prevention first, which means GOOD WIRING and FUEL lines and AUTOMATIC activation of the extinguisher to put out any fire that starts.

On my boat, I chose a AUTOMATIC Haylon System... others used a large CO2 cylinder.

[carioca1232001]

Gary E,

To start with, I was wondering if this topic would fit in better over at Misc Boat Related, but at the same time, it seems most relevant to anyone building a boat, or refurbishing a boat.

Prevention is undoubtedly at least 50% of the solution to the problem posed, but could you expound a bit more on how particular details of a boat´s wiring can actually make a vessel less prone to fire ?

How about the heavy leads that connect the battery/ batteries to the Battery Switch/Switches ? Does it make sense to protect these main branches carrying the brunt of the electrical loading with high-rating fuses ?

Or will the latter blow-out on activating the engine starter-motor ?

[Gary E]

50%?? I think it's 100% PREVENTION is the ONLY way...

As for the wiring, since most original equipment builders do a reasonable job of wiring a boat, or any other machine/car/truck/spaceshuttle, it is my opinion that most faulty wiring comes from the doit yourselfer that thinks, "it's only 12 v, how hard can it be?" This is the area where they make mistakes that they dont even know are mistakes. In a perfict world, maybe some sort of inspection would be required of the plan before the doit yourself guy is allowed to add/alter/convert/etc etc. and an inspection after the changes were made with some stamp of approval... or maybe common sence would kick in and the "it's only 12v" guy would have someone that knows what they are doing actually do it. As for me, I learned what's right and what's wrong while working for the worlds largest Machine Tool builder.

As for fuses in the line starter wire.. I've never seen them.

[carioca1232001]

I think that I may have (unintentionally) de-emphasised the importance of prevention by quoting the 50% figure.

I agree it is most important, vital if you like.

But should for some God-forsaken reason a fire start on board, you would need to detect it at its very outset and then efficiently put it out. The other 50% !

Well short-circuit protection relays exist on electrical power 60 Hz generators , that are designed to blow-open the circuit breakers in case of a short-circuit in the output conductors.

Why may batteries not be equipped thus, if it means a safer operating environment ?

[Uncle Duke]

carioca asks:

How about the heavy leads that connect the battery/ batteries to the Battery Switch/Switches ? Does it make sense to protect these main branches carrying the brunt of the electrical loading with high-rating fuses ?
It does, indeed, make sense and it is highly recommended. Ample Power, among others, makes fuses specifically for this, ranging from 100 amps to 800 amps:
http://www.amplepower.com/products/fuses/index.html

[Gary E]

I do not know why...that's not to say it cant be done that way, I just do not know... but if I have to guess, cost...it woulld cost a lot more than the paying public would stand for.... Hey, as far as I know they dont even REQUIRE Automatic Fire Extinguishers as standard equipment. Pretty expensive items... but so are parachutes and life rafts.

[carioca1232001]

Uncle Duke,
They (Ample) must be unusual blokes, because not even Blue Sea manufacture fuses specifically for this application. Blue Sea fuses do not go higher than around 400 Amps. Thanks awfully for the lead !

Now I am encouraged to hire a power-system protection engineer from my former employer (Rio Light Co.) to help me coordinate the electrical protection system on my boat !

[Gary E]

Ample Power has some books that seem to be a good idea..
http://www.amplepower.com/products/index.html

[pipefitter]

Has anyone that works with marine wiring ever noticed that on any well used boat of say 5 years plus will have wiring issues? As soon as we hear of instrument related/electrical issues, we can bet that one thing will open a can of worms and in most situations, the whole case of cans of worms. More times than not, the customer will need a total rewire than to cost effectively troubleshoot each item and replace as they occur from there on out. Many factory rigs these days are using simple butt splice connectors which will crumble inside their sleeves when disturbed after a time. When we do rewires, we typically bring it up a notch with military spec wiring and connection practices and in most cases, teflon coated wires and cables for high amperage circuits. These are the same type of practices that are used in military systems that will go through environmental and vibration chamber tests repeatedly without fail. It seems overkill until you see how quickly a typical OEM installation degrades in a few years subject to the marine environment. Anyone who owns a boat should be schooled on what to inspect or at least be willing to pay someone who is qualified to 'thoroughly' inspect their systems. One may be surprised how many people don't even know what a proper battery connection should look like. They automatically assume if the instrument lights come on, the battery must be ok.

[carioca1232001]

Has anyone that works with marine wiring ever noticed that on any well used boat of say 5 years plus will have wiring issues? As soon as we hear of instrument related/electrical issues, we can bet that one thing will open a can of worms and in most situations, the whole case of cans of worms. More times than not, the customer will need a total rewire than to cost effectively troubleshoot each item and replace as they occur from there on out. Many factory rigs these days are using simple butt splice connectors which will crumble inside their sleeves when disturbed after a time. When we do rewires, we typically bring it up a notch with military spec wiring and connection practices and in most cases, teflon coated wires and cables for high amperage circuits. These are the same type of practices that are used in military systems that will go through environmental and vibration chamber tests repeatedly without fail. It seems overkill until you see how quickly a typical OEM installation degrades in a few years subject to the marine environment. Anyone who owns a boat should be schooled on what to inspect or at least be willing to pay someone who is qualified to 'thoroughly' inspect their systems. One may be surprised how many people don't even know what a proper battery connection should look like. They automatically assume if the instrument lights come on, the battery must be ok.

At the same time as I was told about the two boats that caught fire yesterday afternoon, there was this young bloke overhearing the heated conversation betwen us senior Club members.........so after a time he chimed in and inquired:

Said he: "I am the second owner of this 4-year old fibreglass sailing vessel and everything has worked rather well, excepting of late, the starting motor that simply dos not manage to fire-up the 30 HP Yanmar diesel engine........the starter motor does kick-in, but shortly thereafter, the diesel engine coughs and spits....as starting-up seems to be out of the question"

I related to him the experience with my twin-engine motor-cruiser and how I had racked my brains to determine why they would not start, specially as the electrical witring had been redone completely some 50- 60 months earlier.

The conversation went on and on, until I related what the battery retailer had to say:

'Your batteries are in perfect order, just look at the massive short-circuit current capability that they were able to generate on the test rig......I would be more than happy to sell you a couple of new batteries...but I honestly feel that you should take a close look at your wiring before we do so, because the problem will persist....... even with the installation of new batteries ....... my intuition tells me that the main battery leads have had it, for one reason or the other......'

He was absolutely right !

Albeit on the surface the wiring looked ship-shape and the ohm-meter on my hand-held signalled OK, I decided to strip some PVC insulation off at mid-length......and lo and behold, the strands of untinned-copper wire had corroded completely....

The resistance of the corroded section of the main leads to the passage of heavy starter-motor current must have been enormous...... no wonder there was no voltage left to spin the starter motor, specially during repeated attempts.......

[paladin]

and there you have pinpointed the major cause of electrical fires on boats......
The wire corrodes on the inside....the smaller wire has a higher resistance, the higher resistance means more current is drawn for the original application, the resistance/high current is like the heating element on top of your cook stove...somethings gotta burn....

[Tylerdurden]

Most electrical fires are caused by corrosion in the wire causing the ampacity (current carrying capacity) to drop. At some point the resistance will cause excessive heat and it will melt insulation of itself and wires next to it.
I cannot stress enough how cutting your wire size schedule close will amplify this problem sooner than later.
Next in line is corroded contacts and similar things happen when they fail.
When wiring its smart to up size your conductors beyond specs and use quality tinned marine wire. Fuse everything and if you run breakers do not get in the habit of flipping it back on when it trips, find the cause.
Several Yachts I have wired are still going strong since being built in the late 80's early 90's but because they were million dollar boats they have been professionally crewed and maintained. Most boats I see that are owner maintained DIY are fires that haven't happened yet.
Before one spends big bucks on all the goodies decide to leave out one high dollar toy and instead invest in quality wire, connections and over current protection. Mount the battery disconnect where it can be reached and seen not where its most hidden and pretty.
When in doubt by smoke or smell shut off that battery switch before any other, then locate and fight the fire.

If anyone needs help on any project feel free to PM me and I will do my best to get you on the right track.

[pipefitter]

I had a customer ask me how he could test his wiring. I said, 'just touch one of them or act like you are going to and they will all start failing'. Seems that all it takes is just a good movement of the harness to bring it all down. Once we redope all the connections on the new wiring, and make easy access to any junctions, it becomes visually obvious if there is any problems. I know of one boat fire on a carbeurated gasoline engine that was leaking gas on the butterfly linkage where the shaft went through the body of the carb. They were all looking for loose lines and such but I found stains in the depressions of the intake right under the butterfly rod where you could see that gas had been filling up there and evaporating. Luckily, the fire was put out with only damage to the wiring to the motor. The shaft had wallowed out the housing on the linkage side.

[carioca1232001]

As Paladin and others have pointed out, corroded wires mean higher resistance, which will definitely be the root cause of mal-functioning of starter motors and other loads.

When the wires have corroded completely, they are virtually open-circuits.

So it may be reasonable to suspect that culprit wires are those which have corroded slightly, not to the point of causing malfunctions and altering the load current substantially, but the energy dissipated in them may have gone up a great deal. (say, 2 or 3 fold)

That said, what would our experts recommend when wiring a boat ?

Use only marine-grade tinned-copper wiring all throughout the electrical installation ? Is this good enough insurance ? Will such wiring last a lifetime ? Or will it just buy time ?

[Tylerdurden]

That said, what would our experts recommend when wiring a boat ?

Use only marine-grade tinned-copper wiring all throughout the electrical installation ? Is this good enough insurance ? Will such wiring last a lifetime ? Or will it just buy time ?

It will buy time, lots more time. Nothing beats maintenance and KISS.
A well thought out harness and plan will save bundles of cash down the road. Quality should not be skimped on here.
I would like to point out one of the biggest problems I see and that is using crappy cheapo crimping pliers. Buy a quality pair I prefer Klein 1005 .
With nice tight crimps and some good heat shrink you can make connections that will last a good long time.

[timfish]

I have been involved in two fires on board myself(one electrical/one due to exhaust) and having been involved in a shipboard firefighting college course.I ve also witnessed three fires up close.wire resistance and shorts can easily and quickly turn your boat into a toaster oven.Fuses are VERY IMPORTANT!They save the boat,equipment,and the lives of those aboard.Onboard fire equipement is usually barley barely enough to save lives let alone the boat.Halon systems are good as long as it is deployed properly.Extinguishers need to be big enough to put out the fire not only suppress it.Most of what burns onboard is very hard to put out.Some modern synthetics are nealy impossible(rope,sails,rubber hoses,plastics and fiberglass).Double the size and number of your extinguishers.Think of how you will deal with the smoke,the heat,and access to the area where fire might occur.When building or adding to a system make access and inspection easy.

[Bob Adams]

Mark makes many good points (BTW I prefer T&B crimping pliers)
I've found most boats over 15 years old need all the wiring removed and redone. Owners just love to to be electrical engineers on thier boats, to very poor effect. I use only tinned wire, always use a guage heavier than required, and use branch panels to limit the long runs of relatively small wire.

[pipefitter]

Another thing to consider is when wiring anything in a wet environment, even when using shrink boot over terminal ends, whenever possible, face the connectors and wire ends downwards. It may not make all that much of a difference but it makes sense. That way, no water/condensation can weep into the insulation jacket of the wires if the dope or boots fail.

[willmarsh3]

Critters can cause fires also.
I rewired a pontoon boat used as a committee boat for the sailing club. I replaced all the wiring with the proper tinned copper stranded marine grade. I also moved the wiring above the platform as there had been problems with muskrats chomping on it below.
If the exposed wires short out....

[Bob Adams]

Another thing to consider is when wiring anything in a wet environment, even when using shrink boot over terminal ends, whenever possible, face the connectors and wire ends downwards. It may not make all that much of a difference but it makes sense. That way, no water/condensation can weep into the insulation jacket of the wires if the dope or boots fail.

Good points. I also use a shrink tubing that is internally coated with an adhesive. Good seal.

[carioca1232001]

I have been involved in two fires on board myself(one electrical/one due to exhaust) and having been involved in a shipboard firefighting college course.I ve also witnessed three fires up close.wire resistance and shorts can easily and quickly turn your boat into a toaster oven.Fuses are VERY IMPORTANT!They save the boat,equipment,and the lives of those aboard.

Good points Tylerdurden, Bob Adams, Pipefitter and other contributors on this thread.

Agree that shorts can be addressed adequately by properly sizing the fuses.

In fact, one can opt for a fuse downstream, by the load, preceeded by a breaker (marine sort) upstream, for good measure.One has to be terribly unlucky for such a setup not to perform when required to .

Now it seems that real sneaky behaviour may be exhibited by corroded wires when the corrosion is below the level that confers inoperability on the end device (load), as then everything seems OK to the boat´s captain, no telltale signs anywhere.

The cenario is complicated further if the corrosion is limited to a splice or to a short section of conductor - lumped over a small section and not distributed - making for rapid build of temperature due to energy dissipation in a small space.

A fuse is left helpless to clear such a fault !. Herein is a modest beginning for an almighty fire !



Onboard fire equipement is usually barley barely enough to save lives let alone the boat.Halon systems are good as long as it is deployed properly.Extinguishers need to be big enough to put out the fire not only suppress it.Most of what burns onboard is very hard to put out.Some modern synthetics are nealy impossible(rope,sails,rubber hoses,plastics and fiberglass).Double the size and number of your extinguishers.Think of how you will deal with the smoke,the heat,and access to the area where fire might occur.When building or adding to a system make access and inspection easy.

We´ll get back to this part of the topic ( the other 50%) once we´ve exhausted the electrical system and engine-related prevention, pipefitter having had some experience with an engine-related fire.