No Insurance Cover Dehumidifiers For Fire Risk on Boats?

lpdsn said:
OK, although I'm very doubtful about the 'much smaller package'. The working parts of fridges don't take up much space at all these days. And they too have a decent control system.
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The condenser for a fridge is quite a big thing and the casing of the dehumidifier beside me is only a smidge over 6" from front to back ... try getting a standard compressor in that.

The control system on mine has a few easy modes and I can also set humidity-on and humidity-off points, louvre swing angle, a timer and a few other things. Not that I do, but I could

It still doesn't convince me that you must have a top-end de-humidifier to be safe when the majority of fridge freezers aren't top-end and are perfectly safe.
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I'm not convinced either. I'd be more worried about cheap ones breaking down than about them damaging anything in the process.
 
JumbleDuck said:
The condenser for a fridge is quite a big thing and the casing of the dehumidifier beside me is only a smidge over 6" from front to back ... try getting a standard compressor in that.

The control system on mine has a few easy modes and I can also set humidity-on and humidity-off points, louvre swing angle, a timer and a few other things. Not that I do, but I could



I'm not convinced either. I'd be more worried about cheap ones breaking down than about them damaging anything in the process.
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Third Winter in my Maeco Junior still going strong (or was on last visit) and at that price I'll replace it actually goes. Yes we will have to wipe off a bit of mould and do a ton of washing though.
 
RupertW said:
Third Winter in my Maeco Junior still going strong (or was on last visit) and at that price I'll replace it actually goes. Yes we will have to wipe off a bit of mould and do a ton of washing though.
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I should maybe have said that I bought mine for use at home because we have a rebuilt wall which needed to dry out ... they say about a month per inch, and this one's getting on for three feet thick. It doesn't have much to do now, but for the first twelve months it was pulling out 10 - 15 litres per day. I wanted something which I was happy would do that without grumbling. Friends have a Meaco (I think) dessicant one which cost 1/3 as much and which they are very happy with.
 
Unless you are a liveaboard you simply do not need a compressor-driven dehumidifier. If the boat is reasonably tight, there is no need to remove more than a fraction of a pound of water per day. Thus, a thermoelelctric effect dehumidifier will be cheaper, smaller, and better able to function in low temperatures. In fact, even this tiny dehumidifier can be run on a timer, just a few hours per day.

What happens if you open the door and let humid air in? A boat full of humid air contains only a few pints of water, so the dehumidifier will remove it quickly. Wasn't that obvious?

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https://sail-delmarva.blogspot.com/2012/12/dehumidifier-vs-desicant.html

Do you need a dehumidifier? Of course not, but the boat will be drier with one, deep into the mattresses and cushions. Mildew will be less and corrosion will be nil. Do you need a New Gen anchor, or will a CQR hold? Sure it will, just not as well. Do we need to sweat what is "best" and always buy it? Of course we don't.
 
An interesting point, TW, which caused me to reach for my psychrometric calculator.

Without going into great precision, air at 25C and with a RH of 95, has a load of approx 20g per metre cube. I suspect you are referring to a rather large boat when you say "a few pints of water".
 
sarabande said:
An interesting point, TW, which caused me to reach for my psychrometric calculator.

Without going into great precision, air at 25C and with a RH of 95, has a load of approx 20g per metre cube. I suspect you are referring to a rather large boat when you say "a few pints of water".
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Yes, the ridiculous upper limit, including some that absorbed into mattresses and such. The point is that most boats are pretty well dried in a day, with lesser amounts coming out of the woodwork very slowly. In fact, to avoid overdrying and cracking, there needs to be some manner of regulation, either by humidistat or by using a very small unit.
 
The oak planks from our sawmill leave the kiln at 8% moisture content; anything lower causes formal stability problems. The planks are delivered to the customer, stacked (if possible) in the room of the property where they are to be installed, and allowed to acclimatise for one to two weeks before being laid. The MC returns to ~12 to 16 or higher.


I imagine that timber on a boat will have a similar figure, so overdrying the air with a big aggressive dehumidifier may well cause movement problems especially between joints, though the span of structural timbers on board will be much smaller than that in houses.

I must take the moisture meter down to the boat and test some pieces under various conditions. Leaving lockers and other crannies open is important to reduce the Rel Hum and prevent condensation on a cold surface e.g. hull interior surface, which may then migrate to stored bedding or food..


I might try reading up on domestic comfort zone figures and see if they can be transferred to on board environment, but with so many differences in body activity, clothing, movement of air, radiant heat, etc., I expect the range of temps and RH to be quite different.
 
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sarabande said:
I imagine that timber on a boat will have a similar figure, so overdrying the air with a big aggressive dehumidifier may well cause movement problems especially between joints, though the span of structural timbers on board will be much smaller than that in houses.
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My home dehumidifier will not go below 40% RH and defaults to a minimum of 60%. I presume that's to avoid issues with distorting timber.
 
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