Tube heaters

We used a 55W green house tube heater (with thermostat) just like this in the saloon of our boat, kept on the water, throughout last winter.

http://www.wesellelectrical.co.uk/hylite-slimline-eco-500mm-55w-tubular-heater-white

It kept the interior noticeably less damp and sweeter smelling - I could tell when the power had tripped on one occasion as I opened the hatch. It has recently been brought out of the loft, and is back in use as I type. I noticed the same heater in a chandlery last winter, at around twice the price we paid....
 
Afloat in Plymouth, I wouldn't be too bothered. The sea temperature there is at its lowest in March and is rarely below 7C and that'll be enough to keep your engine space above freezing.

Even ashore, it'll take a prolonged spell (several days) well below freezing to get it down to -2, which is the typical freezing temp of sea water That's quite rare in the SW.

Ideally you'd drain everything completely, but that's not always possible, so flushing through with antifreeze is the next best thing. I tend not to worry, but I have made a special trip down a couple of times to get a bit of warmth in there over the 10 years I've had the boat. Once I couldn't - too much snow; when I could get down, there was ice on the top of the water tank but no harm done to the plumbing or the engine.
 
Perhaps an unnecessary and further issue to factor in: The efficient production of heat from the energy consumed is only the first consideration but you might also want to give some thought to heat transfer. i.e. if it is just the engine you want to keep warm then a "block heater" as used in cars in N America is going to be more efficient at getting a small amount of heat where it can do the most good.
 
mlines said:
I was advised not to use heaters in the cabin as they promote mould to grow due to the relative warmth, I was advised to just use a de-humidifier which has a drying effect and produces a small amount of warmth as a side effect.

However, as it is a petrol engine boat I do have a concern about electrical switching on and off in an enclosed boat. The engine and cabin are separate and there is never any petrol smell in the cabin, its an injected engine so there is no normal evaporation from a float chamber etc.

Is this ok?
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Well, nobody else has ventured an opinion so.

If you are happy to run a unsupervised dehumidifier 24/7 I would site it high up in the boat. So that any sparking potential is away in the fresher air. It might help to set the humidstat on high and switch the thing with an external timer; experts may be along to confirm or deny this soon.

A small tube heater, without thermostat, could be switched on a timer (in the upper works or even outside the cabin). This should be free of sparking hazard. I feel the trick for avoiding mould growth is good ventilation, think of the heat source as an aid to moving air through the boat.
 
I have a dedicated marine engine bay heater fitted to mine, which I got shipped from the States.

http://www.xtremeheaters.com

It's thermostatically controlled, ignition protected, and blows hot air directly onto the block.

My boat sits in fresh water which on 2 occasions in the last 5 years has been frozen solid in ice in the marina for around a month (= well below freezing).

Remember, even with anti-freeze in fresh water coolant in the block, there is still a raw water part to the cooling system that can freeze/burst in extreme (low) temperatures.

True enough, salt water rarely freezes down south, but in Scotland it does happen on still water during prolonged cold spells.

Either way, having heard first hand the horror stories of damaged blocks, damaged water pumps, damaged heat exchangers and damaged batteries, I'm happy to spend a few £'s over the winter in electricity to protect a valuable asset!

And for the cabin, I've thermostatically controlled tube heaters and desiccant water traps spread liberally around the boat. Never had any problem with dampness.
 
kennyh said:
I have a dedicated marine engine bay heater fitted to mine, which I got shipped from the States.

Remember, even with anti-freeze in fresh water coolant in the block, there is still a raw water part to the cooling system that can freeze/burst in extreme (low) temperatures.
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I thought it was common practice to fill the raw water side of the engine with an antifreeze mixture to prevent this from happening?

I've done this when the boat has been layed-up, ashore and afloat, but obviously doesn't work if you use the boat regularly during the winter months.
 
Ian_Edwards said:
I thought it was common practice to fill the raw water side of the engine with an antifreeze mixture to prevent this from happening?

I've done this when the boat has been layed-up, ashore and afloat, but obviously doesn't work if you use the boat regularly during the winter months.
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Exactly; I usually fill the raw water side up with antifreeze also during the worst of the weather. But doing that while it's afloat does not fully fill the raw water side with antifreeze (I can't fill below the water pump).


I also try to use it during the winter season, and having the automatic heater onboard means I can sleep a little more peacefully in the event of a sudden temperature change.
 
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Ian_Edwards said:
I thought it was common practice to fill the raw water side of the engine with an antifreeze mixture to prevent this from happening?

I've done this when the boat has been layed-up, ashore and afloat, but obviously doesn't work if you use the boat regularly during the winter months.
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If you drain the trap and open the pump cover there will be no water in there to freeze. Probably more effective and definitely cheaper :)
 
Bearing in mind I've a D4 Volvo that is a significant percentage of the overall boat value, irrespective of what anti-freeze I get into the block / coolant system, I'm quite happy to spend some £'s ensuring the engine bay does not get below freezing, and thus risk a block or component failure.

Call it anal or whatever, the comfort of having an automatic hot air system protecting the engine is comforting. Oh and I should have mentioned that I also have a remote monitoring system that sends me an SMS message if the mains power is disconnected or if the engine bay gets below 3C.

Belts and braces!
 
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