Dehumidifiers

One of the useful products of a d/h is heat. As they are not 100% efficient they will give off between 40-100watts via the fan. If you can direct the blown dry air it will help. Dry air feels colder than damp air so it will not be apparent.
 
we have built in dehumdifier which I have always sworn by - never a sign of mould or damp.
However....
it packed in last year and I never got round to sorting it out - after a long wet winter - boat was still dry fresh, and mould free. In a relatively modern boat with a good fixed ventilation sytem maybe we worry too much?
 
Bought B&Q £80 model in 2003 - works on Westerly Seahawk.
Bought a second for home it was so good.
Works a treat, but does use 200 watts and tends to run almost 24/7 in the winter. That can be a big bill from the yard, if they work out how much energy you are using.
Got caught with a big bill for about 300 kw when overwintering out of the water in The Netherlands.

Maybe having some background heating to keep the RH higher might make a less
expensive option.

but it is great having a dry boat and not having to take everything off the boat and lug it back home and try and stuff it in the loft or similar
 
blueglass said:
However....
it packed in last year and I never got round to sorting it out - after a long wet winter - boat was still dry fresh, and mould free. In a relatively modern boat with a good fixed ventilation sytem maybe we worry too much?
Click to expand...

Out of curiosity I had a moisture meter on board (next to an open porthole) during our summer holiday. I was very surprised to find that at evenings when the temperatures dropped, the reading was as high as 86%! (as the temp dropped, dew point was closing). So, if all the vents are left open and especially if there are sudden changes in air temperature, the moisture inside will form on surfaces and create conditions for mould.

In my experience, the build up of mould is not so straight forward, but a result of right combination of variation in conditions.

IMHO, any attempt to keep the conditions inside as dry and stable as possible is going to keep the interior in better shape in the long run, than exposing it to continuous variations in moisture and temperature as often is the case in winter.
 
We considered buying a dehumidifier last year but never got around to it. The boat stayed dry and fresh smelling so dont think we will bother this year.
 
A little heating and ventilation

Refrigeration type dehumidifiers won't do anything below about 6 deg C. They work by condensing moisture out of the air on the cold surface of the coil but the built in controls will limit the operation at those temperatures because of the likelyhood of freezing.

Dessicant type dehumidifers will operate at considerably lower temperatures but as others have said you have to dry the dessicant and vent it to outdide or else you get your own back.

Both of these devices may remove some of the moisture given out by your breath if you are sleeping on the boat in the winter but I doubt if they would stop it condensing on very cold surfaces like windows and frames.

When the boat is unoccupied; just heat it a little. I use a 240 watt tubular heater left permamantely on in the front cabin with the hatch just open on the ventilate position.

My boat, upholstry and bedding stays bone dry.

And yep it's nearly always above 68%RH except in the desert!
 
crunderhay said:
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Dessicant type dehumidifers will operate at considerably lower temperatures but as others have said you have to dry the dessicant and vent it to outdide or else you get your own back.
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Click to expand...

Not quite correct any more... The latest desiccant dehumidifiers like the X-dry and the smaller model we also stock continuously regenerate the desiccant and discharge the water either into a tank or to a drain. Have a look at the details on our website at http://www.boatsheen.com/dehumidifiers.html
 
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