Lay Up, condensation and dehumidifiers

[tom52]

I have always been advised that the best way to minimise condensation without artificial help is ventilation. The more ventilation the better.

However for this years lay up I will have access to electricity and I may use a dehumidifier.

My question is this ........

If I use a dehumidifier should I close the boat up as airtight as possible ?

If I don't close up tight presumably I will be attempting to dehumidify the world ?

 

[fireball]

We didn't bother with air-tight - just closed up as normal.
What I did do on the previous boat was have a companionway cover (bit of old sail material!) which kept the rain off the vent ...

 

[lw395]

Yes, that's true.
What we really need is an automated vent opener to open when the humidity is less out than in!
I want one for my lock up garage.

If you are trying simply to stop condensation, and your elec is metered, it may be best to run a timer and run it when condensation risk is most, i.e late night through to early morning.
If you are trying to dry out a wet boat, then it pays to run the thing when the temperature is highest, as there is most moisture to remove then.

 

[Fire99]

I was thinking of a cheap idea to help a little.

What about some pots with salt in them, in a few places of the boat. Should help absorb the moisture a little.

I think .

 

[Ian45]

Heater

As this is our first year with our boat (only bought in in August) we decided to not take winterise it this year to maximise usage.

We are on an unmetered hook up so the engine bay has an electritic sealed bar heater and we have just placed one in the cabin.

Fingers crossed it will keep everything from either freezing or going damp!

 

[red beard]

Yep I always use a dehumidifier with a humidistat and keep the boat shut up tight as poss never have any problems with damp or mildew. Obviously make sure it has a drain pipe and also make sure it comes on after a power out. I find my marina cuts the power every now and then for whatever reason and in most of the new ones you have to push a button to restart it, no good if you are not around.

 

[Scotty_Tradewind]

I close up completely with dehumidifier.
sealing all vents with some shopping bags, emptying the loo completely with a little disinfectant wiped around, make sure no water in sink waste and a little disinfectant dripped down.
I get a minimum of 4 pints a week possibly more when it's warm and wet.
Mine is a large 'standard' dehumidifier from Argos. Not so efficient when etremely cold but never any damp, mildew or mould and smells and feels right.

 

[BGW]

Yes, that's true.
If you are trying simply to stop condensation, and your elec is metered, it may be best to run a timer and run it when condensation risk is most, i.e late night through to early morning.

At these times it may well be too cold for the dehumidifier to remove any moisture - they have a temperature limit that they will not work below. (varies by make and design) - By removing the excess moisture during the day when it is warmer, there will be less or none to condense out overnight.

 

[red beard]

wee tube heater is the answer to the problem of cold weather and dehumidifiers

 

[Badger]

Dehumidifier and heater

I bought one of these from Force 4 http://www.force4.co.uk/7265/Seago-Portable-Dehumidifier.html and made up the tubular heater in the picture from bits bought from my local plumbers merchant. Great combination, boat is dry and cosy.

 

[VicMallows]

An observation is that when many years ago my boat was in a sheltered marina, it suffered badly from condensation and consequent mould. (heaters were impractical on the shared coin-in-slot meters; dehumidifiers had hardly been thought of).

As soon as I moved to an open swinging mooring all such problems vanished! (I keep a forward dorade vent facing forwards on the mooring to maximise air flow).

Vic

 

[LittleSister]

Lots of ventilation is the answer, plus give the boat a good internal wash/clean before laying up to remove the salt from all surfaces (it absorbs moisture from the atmosphere and stays damp) and the dirt which mould lives on.

By contrast, if you do run a dehumidifier you want no ventilation, otherwise you are trying to dry out the earth's atmosphere and the de-humidifier will have an endless supply of moisture to extract.

With laying up there's no need for de-humidifiers if there's adequate ventilation, but few production boats have enough ventilators. The other big problem is with a boat that's in commmision during the winter. There'll be lots of condensation and salt around after each trip, especially in a small boat.