Tube Heater under engine - next to fuel tank?

kennyh

kennyh

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Hi Guys

I'm thinking of putting a tube heater under my engine in case there's a drop in temperature. It's winterised just now, but I plan on getting it going this weekend when I move it from my driveway to the marina.

Q. My engine sits right next to my fuel tank (petrol) and I'm concerned that the cheap tube heater wouldn't be ignition protected, and could spark any fumes lying around down there. Have you used a tube heater safely to do something similar?

Kenny
 
again a bit late now,i have used them for year's without a problem,how ever i would not put them anywhere near a fuel tank!!!!!,come on think about it,regards m m 1. /forums/images/graemlins/shocked.gif
 
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how ever i would not put them anywhere near a fuel tank!!!!!

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That's what I'm thinking - the engine sits approx 2 foot away from the engine (Mercruiser V6).

And as edited above - the weather if forecast to down to freezing where am I next week.
 
Hi,just make sure you drain it down,or better still disconect the sea water inlet pipe&run some antifreeze through,regards m m 1.
 
Come on chaps - surely this would be OK

After all, assuming the fuel tank is properly and safely installed and vented externally, there will be no fumes in the engine bay and even if the stat on the resistive heater (therefore limited arcing) activates, there is nothing to ignite?

My reasoning:

1) The engine when running will get just as hot as the tube heater and if thats next to the fuel tank, then whats the difference?

2) The alternator electrically is surely more of a threat than the instantaneous switching of a resistive load?

I think positioned sensibly and set to a low-temp it would be just fine! /forums/images/graemlins/cool.gif
 
how silly of us to think that there would be petrol fumes/vapour in an engine bay after the engine had been run!!!, i wonder if the 240volt input is as safe as you think,regards m m 1.
 
I have used tube heaters in the engine bay of a petrol boat much like you have described. Here's what I did:

Unless you are going to leave the tube heaters on 24/7 you will be either putting them on a time switch or more likley a thermostat. Any sparking is going to happen at these switches.

I put the tube heater in the engine bay and ran the wiring out of the bay into the cockpit where I loctaed the thermostat, under cover to protect from the rain etc. Set to 5*C and then when it clicks on the spark is away from any potential fumes.

Realistically it has to get very cold to do damage. If the boat is in the water the water will insulate it somewhat, and if the water is salt, it will have a lower freezing point anyway.

You could probably set the thermostat to somewhere nearer 0*C but I like to give it time to heat up before the temp drops too low.
 
Yep - as we know this installation assumes the engine is cold, otherwise the heater would be off (ignoring previous chaps rant).

I dont think arcing would be a significant problem, assuming the heating element switches a resistive load, so what you suggest sounds eminently sensible to me, and good advice.

I might even suggest setting the stat even lower (if external) to say -1 or even -2C for the very reasons you suggest!
 
I had one in the engine bay of my last boat (petrol) it has no source of arcing or ignition, for safety i had the thermostat outside of the engine bay, so no switching (arcing) in the engine bay.
 
When the engine is running, the fans are also on, plus the air in the engine room is being changed rapidly as it's sucked through the air filter, so the vapours may not hang around long enough to ignite. When the boat is stationary, fumes have time to gather in the bilges, so I don't think the engine running comparison necessarily applies.

I think the risk is low, but it is possible that a fuel tank could be ruptured in a violent landing at sea, and then slowly seep fuel into the bilges whilst the boat is at rest, so I think the idea suggested above, which removes potential sources of ignition, is a good idea.

If he wasn't banned, there would be a forumite telling us that he's lucky to be alive after having petrol accumulate in the bilges of his new boat, so it can happen.
 
I accept of course that it's possible for fumes to build up in any engine compartment, hence fans installed. But I do not accept that this tube heater itself would present any greater threat than the host of other electrical equipment that dwells within this area.

In fact, this heater IMHO presents an equal or some may say significantly less of a threat than say: battery chargers (230v primary), starter motors, alternators, ventilation fans, relays, contactors, pumps, pressure switches, battery terminals and the like. Many of which switch or are themselves inductive loads albeit their switching mechanisms are equally well concealed!

So my risk assessment would have to be:

Likelihood = (1) Very Low
Severity = (4) Severe Injury

And if you fit the stat externally, which seems a sensible additional precaution, I personally would have no hesitation whatsoever in fitting a tube heater below an engine!
 
Many of you have said it has to be very cold to cause damage. How about around -3/-4 on fresh water (with it snowing).

Do I need to dash up (to my marina on Loch Lomond) and pull the drain plugs? It was winterized until Sunday when I put it onto the water due to a berth becoming available.

Kenny.
 
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