JumbleDuck
Well-known member
Yes, that's what I meant. Sorry if it was unclear. Both of them are on Hive smart plugs.
Dehumidifier or not?
- Thread starter pessimist
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Martin&Rene
Active member
Over the last 2 days whilst we are winterising the yacht, I run a heater and dehumidifier for a few hours in each of the cabins and then overnight in the saloon, whilst we are staying off the yacht. Thus the aim is to leave it as dry as possible. If you leave a yacht with moist cushions etc. then you should not be surprised if they go mouldy and smelly. Then over the winter it is just shut up, with the small gap between the entry hatches being the only small amount of ventilation. I consider last winter was a good test as the yacht was left unattended from mid November to July and it was perfectly ok when we opened her up and met with my wide's approval . The couple of moisture traps that we put in the electronics area were fuller than normal.
Like Jumbleduck, our yacht is on the Clyde and so the daily variations in temperature are not too high. I can well imagine that in certain areas down south that a yacht would experience much greater temperature variations ,warm sunny days and freezing nights, and so the yacht will "breathe" and this could mean that cold moist air is pulled in each night. So as always, the answer may depend on your particular operating conditions.
We actually use a dehumidifier in summer to keep the yacht fresh throughout the year.
Like Jumbleduck, our yacht is on the Clyde and so the daily variations in temperature are not too high. I can well imagine that in certain areas down south that a yacht would experience much greater temperature variations ,warm sunny days and freezing nights, and so the yacht will "breathe" and this could mean that cold moist air is pulled in each night. So as always, the answer may depend on your particular operating conditions.
We actually use a dehumidifier in summer to keep the yacht fresh throughout the year.
thinwater
Well-known member
I'm in the dehumidifier camp, both my F-24 and PDQ 34. I'm an engineer and understand ventilation very well.
Peltier type. They can operate sub-freezing without damamge, so long as they get a defrost most days. They don't pull a lot of water, but it's enough. Drain continuously into the sink.
In the cat, one in the port hull is enough for the whole boat. If the doors are all open, enough air circulates.
Others have mentioned that there should not be water. My boats don't leak. But the area around the companionway is far from air tight and I'm sure the air changes once every day.
Without a dehumidifier, with good ventilation they are quite OK. With ventilation they are as fresh as home when you lay your head in the pillow, no mold-irritated congestion in the morning. No fooling around with tipping cushions and leaving lockers open. Just clode the door and go home. I sail all winter.
Peltier type. They can operate sub-freezing without damamge, so long as they get a defrost most days. They don't pull a lot of water, but it's enough. Drain continuously into the sink.
In the cat, one in the port hull is enough for the whole boat. If the doors are all open, enough air circulates.
Others have mentioned that there should not be water. My boats don't leak. But the area around the companionway is far from air tight and I'm sure the air changes once every day.
Without a dehumidifier, with good ventilation they are quite OK. With ventilation they are as fresh as home when you lay your head in the pillow, no mold-irritated congestion in the morning. No fooling around with tipping cushions and leaving lockers open. Just clode the door and go home. I sail all winter.
jdc
Well-known member
The humidity outside the boat averages about 85% RH over the winter down here in Cornwall. Fabrics can be assumed free of mould growth if humidity is less than ~60%, preferably around 50%. Thus one simply can't rely on ventilation or drying the boat out once and for all and then sealing it to keep the boat dry enough. It's not a question of leaks I think.
Here is an example from today on my boat:
This morning someone came aboard to service the engine and opened it up of course, so one can see the humidity rising from about 12 hours ago to around 8 hours ago (it's 10 pm while I'm writing this). I feel that the boat is better with the dehumidifier, and as it's quite well sealed over the winter the dehumidifier doesn't have to work that hard and so it's pretty cheap to run. I'm not saying that if electricity is not available it would be a disaster, but since electricity is available in my yard and I pay for that even if I don't use any, why not run the dehumidifier (desiccant type btw)?
Here is an example from today on my boat:
This morning someone came aboard to service the engine and opened it up of course, so one can see the humidity rising from about 12 hours ago to around 8 hours ago (it's 10 pm while I'm writing this). I feel that the boat is better with the dehumidifier, and as it's quite well sealed over the winter the dehumidifier doesn't have to work that hard and so it's pretty cheap to run. I'm not saying that if electricity is not available it would be a disaster, but since electricity is available in my yard and I pay for that even if I don't use any, why not run the dehumidifier (desiccant type btw)?
salar
Active member
I haven't experienced damp or mould in my boat for the last 25 years of keeping it afloat, and never needed a dehumidifier. The key is having not just ventilation but end to end airflow. We have a solar powered vent at one end of the boat extracting air, and an open vent at the other to let fresh air in. Air movement will inhibit mould which needs static air in order to settle, so I'm told. If you want to go the to hassle and cost of a dehumidifier, feel free!
anoccasionalyachtsman
Well-known member
I have an open keelboat.
No cover, auto bilge pump. Well-ventilated.
I get black mildew under the deck.
No cover, auto bilge pump. Well-ventilated.
I get black mildew under the deck.
Robin
Well-known member
We live on board in UK and run a dehumidifier 24/7 on max extraction that way we see no condensation on windows have dry bedding and smell sweet ours is an Argos compressor type by Ebac and whilst it could be set to drain overboard it is more convenient to monitor it and empty the tank daily, usually completely full, so about 5 litres every 24 hours.
Stemar
Well-known member
This is the trick on a "dry" boat. Either that or a dehumidifier, but not both, or you're just trying to dry the marina. If the boat isn't dry, do something about that problem if you can.
doug748
Well-known member
I think the OP's plan could work very well.
I have used both.
Hell of a slog to put a household unit on a keelboat and it gets in the way on a small vessel.
When this topic was discussed recently we were told how safe dehumidifiers were. A forum member had a dehumidifier boat fire during the course of the thread. What are the odds. : -{
.
I have used both.
Hell of a slog to put a household unit on a keelboat and it gets in the way on a small vessel.
When this topic was discussed recently we were told how safe dehumidifiers were. A forum member had a dehumidifier boat fire during the course of the thread. What are the odds. : -{
.
johnalison
Well-known member
It would be hard to ventilate my boat without compromising security, and even then, there is too much soft furnishing to take home.
I have had a compressor dehumidifier that would restart when used with a timer and one that wouldn’t. The latter had the membrane type of on/off switch now common instead of a proper knob. I now use a desiccant one on a lower continuous setting which is effective and economical after an original burst.
I have had a compressor dehumidifier that would restart when used with a timer and one that wouldn’t. The latter had the membrane type of on/off switch now common instead of a proper knob. I now use a desiccant one on a lower continuous setting which is effective and economical after an original burst.
pvb
Well-known member
I don't use a dehumidifier, and I don't take any soft furnishings home. Seems to be OK.
duncan99210
Well-known member
The small boat lives in Cornwall, ashore from about now until March. No dehumidifier, no ventilation beyond a mushroom vent. I get a bit of mildew if she’s left more than a few weeks between visits but nothing to worry about and not on the upholstery.
Never had a problem with the boat in Greece, despite it being warm and wet during the winter. However, she’ll have been shut up for 18 months by the time we get to her next year, so lord knows what we will find....
Never had a problem with the boat in Greece, despite it being warm and wet during the winter. However, she’ll have been shut up for 18 months by the time we get to her next year, so lord knows what we will find....
JumbleDuck
Well-known member
I can't help wondering how people whose boats are so leaky and smelly that they need a dehumidifier get through a summer cruise. Maybe they never leave the marina.
Halo
Well-known member
Once you have experienced a nice dry boat after leaving a dehumidifier running I doubt you will want to do without one. My Meaco keeps the humidity at 50% +0/-5. The secret is to seal her up tightly. A trick I find useful is to cling film the head otherwise it will get dried up. The crisps and biscuits stay crisp the cushions bone dry.
pvb
Well-known member
I hope you remember to remove the clingfilm on the head...
thinwater
Well-known member
I think it is pretty obvious that people have two different levels of sensibility and never the twain will meet. My cat, for example, has dusty dry bilges, loads of ventilation, and it is still fresher if I run a dehumidifier. But some people are not sensitive to the difference. I appreciate the difference, my wife appreciates the difference, and that is enough for me.
A boat that is closed up (with ventilation) and a boat that are wide open on cruise are not at all the same thing at all. Lockers open and close, hatches are wide open, bedding is fluffed and aired. It's a waste of time to compare them.
To each his own.
A boat that is closed up (with ventilation) and a boat that are wide open on cruise are not at all the same thing at all. Lockers open and close, hatches are wide open, bedding is fluffed and aired. It's a waste of time to compare them.
To each his own.
salar
Active member
I'm wondering if people are trying to replicate the air quality of a new build high spec executive home....on a boat? When I started boating many decades ago we assumed we would get wet and stay damp a lot of the time. We have come a long way since then but after all, a boat is sitting on water which is very wet.
Whitlock
Active member
You've hit the nail on the head. The only way a dehumidifier will work properly on a boat is if you completely seal the boat up. Otherwise you are just introducing fresh humidified air from outside.
Do you have any woodwork? If you do it will completely dry out and start to split.
johnalison
Well-known member
Humidifiers have different settings. It is not necessary to make the boat shrivel up inside. A moderate setting will do the job perfectly well.
billyfish
Active member
Just installed a planer hot air blower with timer. Nervous about setting the timer for it to come on for say a hour every couple of days as sure dries the boat quickly. Sitting on a mooring. Any one do this.