Battery / Fuel threat?

[castamasta]

Hi All
Had a brief discussion awhile back about the dangers of battery's near fuel tanks under floor.It was mentioned that having my fuel tank underneath my forward casting platform aswell as my bowmount battery could lead to a possible explosion.I understand the theory behind this,but have not had problems in the past and cant see why a battery would spark anyway.Also, i have only put the tank and battery in the purpose built area the manufacturer had built into the boat.I did buy this boat second hand just recently and the previous owner had fixed the forward battery on the floor outside away from the tank,so he obviuosly thought it was an issue.I would love to hear peoples opinions on this,as i obviously dont wish to create a potential serious incedent.
Cheers, Gav.

[Fed]

It's a bit hard to say without knowing exactly what you've got there Gav.

I'd make the fuel vented to the outside of the boat, ventilate the enclosure (for hydrogen gas as well as petrol vapour) and don't use wingnuts on the battery terminals.

Other than that I'd feel OK with it, got any pics?

[castamasta]

Hi Fed
No pics but could get some.I have a seajay territory 4.35.There are two departments under the front casting deck.One tray for a battery to drive the bowmount,and one behind it [towards the stern ] for a 25lt portable tank.The battery is only used for the leccy and is housed in a battery box.Interested in why"no" too wing nuts,and still dont understand how it could spark.
Cheers, Gav.

[Tickleish]

Hey Gav,

I think the portable tank under their with the battery is a very bad idea. The portable will vent all that gas under the floor and then you just need a spark from a loose connection on the battery & BOOM.

As Fed said, wing nuts because you get lazy and tighten with fingers would come loose quite easy with everyday movements of a tinnie.

[castamasta]

Hi again Fed.....would replacing the portable tank with a sealed tank [plastic or alloy] and vent it outside of the storage area fix this problem ?
Cheers,Gav.

[Si]

Hi again Fed.....would replacing the portable tank with a sealed tank [plastic or alloy] and vent it outside of the storage area fix this problem ?
Cheers,Gav.

yes it would mate if you wanted to go that far into it.
Basically seperate ignition source and hazardous area. Can you divide the two areas in some way and seperate the battery and the fuel tank ensuring no vapours can enter into the battery compartment? May be easier and cheaper than putting in a cruise tank.

[castamasta]

G,day Si...It would be difficult to completely seal off the two compartments to ensure it would be vapour free,i dont mind paying for the right setup as long i can make it safe and still have everything underfloor and out of the way as i like it,thanks for your advice Si & Fed its very much appreciated.
Cheers,Gav.

[tunaticer]

I would be much more worried about the battery being in a sealed environment than mixing it with fuel vapors. Hydrogen is much more volatile than fuel vapors and much easier to set off. Both items should be in non sealing areas with adequate ventilation. Mixing both in a ventilated area is not a problem.

[fandtm666]

this is an interesting discussion , i am rebuilding and was looking at placing both the tank and batteries
below the floor in separate areas and was just going run a 1' pipe to each area with a external vent
like the ones on the fuel setup.

[tunaticer]

this is an interesting discussion , i am rebuilding and was looking at placing both the tank and batteries
below the floor in separate areas and was just going run a 1' pipe to each area with a external vent
like the ones on the fuel setup.
A simple piped vent alone will not vent off a closed area it will just hold the vapors there without removing them. You will need airflow.

[Si]

I would be much more worried about the battery being in a sealed environment than mixing it with fuel vapors. Hydrogen is much more volatile than fuel vapors and much easier to set off. Both items should be in non sealing areas with adequate ventilation. Mixing both in a ventilated area is not a problem.

yeah good point. i meant generally from each other rather than completely sealed from atmosphere

[fandtm666]

thanks for that tip , didnt think of the needed air flow

[cgibbo308]

Hi All
I understand the theory behind this,but have not had problems in the past and cant see why a battery would spark anyway..

Lets say your trolling along on your bow mount. You get a bit of weed, or more likely, some line some one has let float away tangled uo in your prop and it wraps up tightly. it may cause some damage letting water in, over time it may jam up. it will draw heaps more current than normal, the battery wires maybe getting a lil long in the tooth and cause a spark or just burn and catch fire. not likely but you never know. and from memory when you charge a battery you get hydrogen gas as a by product, so acid, hydrogen and a spark all next to a fuel cell thats may not be vented in the best way could end a day fishing kinda fast,, and badly.

just a thought.

[oldboot]

The key here is ventilation and lots of it.

I heard of a first hand account of a bloke getting his eyebrows frizzed ( and his undies soiled) from the hydrogen from a battery held under a cowl in an industrial machine, recently..lucky:o.

While they still require ventilation, sealed batteries reduce the battery side of the risks considerably.

The whole wing nut thing is very much a point of contention and discussion..best to use hex nuts and spring washers or nylocks and fit an anderson plug & socket in the line for disconnection...or a battery switch for isolation.

As for the whole fuel issue.....
There are a whole pile of fuel safety issues that are pretty commonly ignored in small boats.

What is done in small boats every weekend would frighten the bjesus out of anybody with a serious fuel handling background.

Hell a certain popular brand of off shore boat has a fuel filler right in the middle of the floor......why are people not screaming holy $h!t.

Every summer we have boats burn for one reason or the other.

Petrol fumes have the tendancy to linger arround and settle into low parts of a boat......hydrogen from the battery being lighter than air will get away if it has the slightest chance..fuel fumes will just happily sit there in a space or compartment or a low lying area.

In the worst case the whole hull of the boat can completly fill with fuel vapours up the the gunwals..and with no air movement it will just sit there.

As such no fuel tank that is not vented and filled from outside the boat should be enclosed in any way.

portable tanks in open boats rely on air movement from wind or the boat traveling to clear any lingering fumes.

Our problem is that we have gone from carrying portable tanks in bare bones open boats, to putting decks and enclosing things and not changed our expectations.

So if you are carrying a portable tank, it should be where the breeze can blow the fumes away.

cheers

[johncar]

Yeah oldboot, my boat has the fuel filler right in the middle of the floor, can't say that I was impressed by that, but at least I am aware of the hazards and being a trailer boat with open scuppers at the stern, it should be well ventilated by the time I reach the ramp and power anything up. Would have prefered an external filler but a major job to do now :\
I guess one advantage of the floor filler, it eliminates filler plumbing leakage possibilities which I have seen at times also..