Low heat on boat during winter - encouraging mould?

[srah1953]

Is it a good idea to keep a low heat going during winter in UK? I ask because it has been suggested to me that a low level of heat just encourages mould. You want to protect from freezing so what temperature should a thermostat ideally be set at, or if freezing is unlikely have no heat at all?
Thanks

 

[pvb]

I don't heat the boat in the winter, but it does stay afloat in a marina, so freezing is unlikely. Ventilation is the best way of stopping mould.

 

[srah1953]

Thank you

 

[Tradewinds]

70 degrees Fahrenheit

Most molds need temperature of 70 degrees Fahrenheit (20 degrees Celsius) or more to grow. Air conditioners to regulate the temperature of your house can help prevent mold growth. For more information about what the common causes of moldare in the home go to Mold Causes.

How to Prevent Mold

 

[maby]

We run a tube heater in the engine bay on a frost setting to remove any risk of expensive damage. We don't heat the rest of the boat while we are not there, but we do spend a lot of time on board during which we have the Webasto running flat out and the dehumidifier.

 

[Momac]

I use a dehumidifier .
https://www.appliancesdirect.co.uk/...umidifier_electronic_control_dd8l/version.asp

 

[srah1953]

"Most molds need temperature of 70 degrees Fahrenheit (20 degrees Celsius) or more to grow. Air conditioners to regulate the temperature of your house can help prevent mold growth"
.... and I thought my friend knew everything .... But, more seriously, I live in Ireland and we don't have many days in the year >20 C° but we sure have lots of mould.

 

[Tradewinds]

Take my Google research with a pinch of salt

Personally I use a dehumidifier

 

[SiteSurfer]

The ventilation vs dehumidifier debate rumbles on - i personally use a desiccant Maeco humidifier, which seems to achieve what I want most effectively. I will not however argue that adequate ventilation also works - it’s just not my chosen path.

 

[pvb]

I hope those of you using dehumidifiers are well insured. Only a month ago Iain789 posted photos of his boat after his dessicant dehumidifier caught fire. The boat is a write-off.

See here - Condensation?

 

[[70521]]

I am in the ventilation camp.

 

[PetiteFleur]

I have dorado ventilators in the saloon and the circular type in the heads and stern cabin. Also a small tube heater in the saloon. Forehatch left on ventilation mode. Never had a problem with mould.

 

[Refueler]

At present I have a Frost-Protector heater running in my boat ... its basically a convector with max 500W but can be temp regulated down to about 200W ...
Its in there while outside temps hover in the 0 to +4C mark ... at night it drops to about -2C .. so I want to be sure nothing freezes such as the auto-bilge pump under the cabin sole.
At these temps - its often drizzle and being an older boat - cannot stop water collecting. So bilge pump stays on auto.

Mould ? No ... not from the heater use.

Once temp dips steady into minus - then I switch off the auto bilge pump, lift it clear of the bilge so no chance of freezing in any residual water ... heater off once I've run anti-freeze through raw water system of engine . gearbox ... then close her up for winter.

About 3 months later open her up to air.

 

[sgr143]

I use an 80W tube heater on a frost thermostat, plus the boat has dessicant-tablet dehumidifiers ( Kontrol KT05071 Mega Moisture Trap-Off-White: Amazon.co.uk: Car & Motorbike) in the saloon, aft cabin and forecabin. We've had no trouble with mould and there's rather less chance of a fire (very sad to see the picture at post #10). The dehumidifiers stay on board all year. I first put them in to see if they would stop the aft cabin ceiling getting so damp with condensation when I was asleep with the windows closed in chilly weather, as to drip on my face. Instantly effective and I've used them ever since. The pucks need changing 3 or 4 times a year; it's a cost, but not a major one.

 

[Hoolie]

I don't heat the boat in the winter, but it does stay afloat in a marina, so freezing is unlikely. Ventilation is the best way of stopping mould.

A bit of a rash assumption.
About five years ago we had frost damage to our calorifier that was close to the water line and has had to be replaced.
Our boat is berthed all year round on the Med near Béziers ... ...

 

[RupertW]

I am in the ventilation camp.

You can always tell when people believe in ventilation as the option. The smell hits you like a sledgehammer when they open their boats and proudly say, “See, my boat doesn’t smell at all”.

That’s why the argument will never be resolved.

 

[anoccasionalyachtsman]

You can't get much better ventilation than I have - an open deck keelboat which is left without a cover.

It has a healthy mildew culture under the foredeck within a foot or so of a 15x4ft cockpit.

Dehumidifier if you have a roof. I'd be interested to hear which brands the dehumidifiers that have caught fire were. I buy Meaco.

 

[Momac]

I'd be interested to hear which brands the dehumidifiers that have caught fire were. I buy Meaco.

Some people see risk in everything. I am surprised such people go boating.

I guess if you look hard enough on the subject of any type of electrical product or machine or any activity there is probably evidence of something going horribly wrong.

It seems compressor type dehumidifiers are considered slightly greater risk compared to the desiccant type. On both the regular cleaning of air filters is important.
Are Dehumidifiers A Fire Risk : What You Need To Know

.

 

[ShinyShoe]

Someone posted 20C for mould. I'd say you get optimal growth at those temps but 15C is very growable and growth can occur 5 - 10C. This is why food fridges run 0-5C as it makes growth much much slower. So a frost triggered tube heater keeping a boat at 4C - fine. A convector heater blowing out 40C+ hot air across the boat and raising the whole cabin temp to 12C might be less of a great solution.

Moisture is also important for growth. So a dry 6C boat will probably be fine. A damp 6C may not be..But a dry (unless humidity <5%) boat at say 15-20C boat may not be.

Heating air causes it to be able to hold more water so water in bilges etc evaporates into that air. When that air then touches a cold surface it can't hold the moisture and so water condensation occurs which means your previously dry surface is now a damp surface and at some point sun etc may well warm it meaning mould can grow..

Ventilation would help that dry out before the sun warms it. Ventilation makes you less likely to get pockets of 20C.

Dehumidifiers stop it getting wet.

*Dry bilges* matter

If you open up a dry boat on a cold damp day you let in damp air that then needs to loose the moisture. The ideal would probably be to dehumidify for 48hr afterwards then click to ventilation

 

[pvb]

You can always tell when people believe in ventilation as the option. The smell hits you like a sledgehammer when they open their boats and proudly say, “See, my boat doesn’t smell at all”.

My boat doesn't smell, if it did my wife would never come aboard.