tubular heater frost protection

[STILL AFLOAT]

Hi All.
I have purchased a Broom 37, that will be berthed on the Thames, with shore power.
I will not be on it for part of the winter, so as a frost guard I was thinking of using four of those tubular greenhouse & attic heaters ?
If I put one under each of the water tanks in the aft cabin, and one under each engine ? Would that work ?
Also, not having a clue about this kind of heater, how long would the tubes need to be, to do the job ?

I am not expecting them to heat the boat, just protect the 2 water tanks & engines.

I did contact Dimplex, about heat output vs length etc, and got a quick reply :
Sorry our heaters are not intended for use in nautical vessels, so unfortunately we cannot help you.

Any information, will be greatly appreciated.

 

[andrewbarker]

I used them in my 36 ft Ranger and they did a perfect job of frost protection. I had 2 x 4 foot Dimplex heaters. I think the key is to have proper thermostatically controlled ones.
The danger, of course, is that thermostatically controlled ones are switching on and off without marine spark protection.

 

[robrennie]

Hi,

I have taken a slightly different approach and used Oil Filled radiators. They have a thermostat on them so you can set to frost protection only.

The reason I chose them was that if there was a fault in the thermostat, being oil filled, temperature could never rise that high and cause a fire risk.

Don't forget, heat goes to cool areas, so don't worry too much about close proximity of heaters, over time the temperature will even out.

On a 29ft boat, I fitted the two smallest units available from Argus, from November to March it cost £50 in electricity to run. One was in the engine bay and one in the cabin. The whole boat remained dry throughout.

Spark protection is an interesting point, I felt that as my boat is diesel and the engine bay is vented that the risk was low - but I am not an expert in any way on this subject.

 

[Momac]

I drain the domestic water off but have a small thermostatically controlled radiant frost protection heater (bought some years ago\) which I locate near the calorifier.
Also I have one large a tube heater in the engine bay between the engines . this I have controlled by a B&Q temperature controlled adapter set to switch on at 5 degrees.
Some people do nothing but they will learn a lesson if we get a hard winter.

 

[jct1981]

Similar to Martyn, I drain all domestic water off, not forgetting to disconnect the pump and blow through with a dingy pump. In addition don't forget to drain the calorifier.

Heater wise, I go completely overboard, and have a large greenhouse heater in front of the engine, plus two small ones mounted on wooden boards under the engine. These are plugged into the calorifier socket in the engine bay via a thermostatic switch (don't forget to leave the 'water heater' turned on). I also have a couple of oil radiators in the cabin, again, on a B&Q thermostatic switch.

 

[STILL AFLOAT]

Thank you all, for your input and explanations.
Now, to do the shopping list.

 

[No Regrets]

I use a 2kw heater in the front cabin (set on 1kw and low, in fairness!) and some greenhouse heaters in the rear cabin, and not only have a toasty boat every time I step on board, as well as a nice dry interior, but never had any freezing issues. The £100 electricity bill for three months is nothing compared to winterising the engines, and the boat is all ready to go every time. The engine bay is centrally mounted with the shaft drive, but the hull isn't the source of freezing anyway!