Dehumidifiers for winter storage

[Guest]

I am planning to winter afloat in a Marina and with the luxury of power would like to run a dehumidifier. The problem is which one, how best to convert it to empty over the side, how many hours a day should it be on etc etc? Anyone with experience of having done this? Yachting press- how about an article?

 

[Guest]

Fine question! I've seen the 'marine' version for sale at about 300 quid plus VAT, but I know I can get a 'domestic' one for 200 or less. Most people seem to stand it next to the sink, and run the hose into the sink. Does it need to run continuously? Would a 'normal domestic' mains timer be OK?

 

[Guest]

I've done this. They need to be as low down in the boat as poss. Mine just chucked into the bilges. I used a B+Q 180 quid (or whatever) one. I ran a timer on the 240 plug (shorepower) to have it on a few hours a day. Duvets and other textiles squeezed into plastic bags and bags stored on high shelves avoided mildew. Best results of course take the matresses home in nice central heated house if leaving boat alone over winter. Unfort I have no idea as to how much water was extracted - but there was evidence of quite a bit of water coming out (from marks in bilge near pipe) , and no mildew/damp in boat a few months later.

 

[peterg]

Dehumidifier for winter storage

We put a dehumidifier on board whilst on the cradle in the car park during December-March and left it on board once back in the water. On land we left it to empty overboard via the sink but once relaunched it was safer to use the internal tank (about 8-10 litres) as there was no way to put it that wouldn't give the possibility of falling over if the boat was bumped about a bit (by other boats or weather). Mine has a humidity level switch so you don't dry the boat out too much as then the veneers can start to shrink and we left it on a medium setting for 4-5 hours a day and then turned it down a bit when back in the water as the temperature was heating up a bit with less chance of condensation (it took over three weeks to fill the tank and switch it off in May when we were abroad on holiday).

BTW - B&Q do them from £99 and they are just as good as the chandler's ones at three times this price (I think I paid £150 to get one that had an internal tank as well as 'overboard' option plus the humidity level setting)

 

[robp]

Get a B&Q one that will stand IN the sink. Then it won't go anywhere. Domestic timer is OK.

 

[peterg]

blimey, how big is your sink?

I haven't seen one small enough to sit in mine (on a 31' motorboat)

 

[Guest]

Re: how much water should they produce?

A few litres doesn't sound very much does it? I'm sure ours must've got more than that. The bloke in the marina said no good in the sink cos it is not low enuf, what with all the low-lying skulky moisture being low in the boat, rather than in the sink. Think it would have to go some to shrink the wood, non?

 

[Guest]

Re: how much water should they produce?

Never heard the 'low as it will go' thing. Any idea why?

It's no problem, cos I can put it on th efloow, lift a hatch and drain it straight into the shower sump, whence the auto bilge pump should deal with it.

On the B&Q note, I see they do a 'Frost Guard' 300W thermostatic heater for 15 quid or so. Would this be suitable in the engine bay, does anyone know? I remember someone saying something about the oil filled tube things you find in greenhouses...

 

[robp]

We have to take the dinghy out first! No, it's just a regular double job. There is a unit in B&Q right now which is about 400mm X 250mm. (Just a guess).

 

[Guest]

Re: how much water should they produce?

It should be low in the boat cos that's where the water moisture is. No good in the sink, cos all the moisture is skulking at floor level. Do you have a hatch in the saloon foor you could open and jam it down there?

Careful- your 15 quid frostguard thing will be a lectric fan heater type thing and ignite things. You need the oil filled things that look like a crap readiator with no actual naked element. Or alternatively, soddit, cos after all all the lorries in scotland trundle about fine in winter don't they? And swedish volvo engines, they'll be ok too.

 

[Guest]

Re: how much water should they produce?

Hatch in the sole, so that's OK. Good point bout the heater. Definitely don't want hot element exposed to air, so oil filled it shall be. They have these little 'Frost Guard' things in the bog/shower block in the marina, but I've never looked to see what the element looks like...

That aside, I presume the oil filled type is OK to leave in the engine bay. With no raw water seacocks (AD31P's), I do not want to let the thing get cold...

 

[Guest]

Re: seacocks

Oh alright, yes nice oil filled thing in the engineroom will keep it warm. But the car get left out in the drive in minus whatever, and no nice ambient water around to mostly (on coast) stay above freezing?

Um, surely it has raw water seacocks? Or does it have no raw water cooling? Dunno.

 

[robp]

Re: how much water should they produce?

Can't say I measured it. Couple pints a week?? Re the heater, I use those sealed tubes, although I'm not sure that they are oil filled? They are cheap and effective. One in the engine bay (2 foot)and one moved around the cabins. (4 foot). Put them on a board to protect surfaces and warn the kids. They look good to pick up and play with, as mine found out on a brokerage boat.

 

[robp]

Re: how much water should they produce?

Surely they will grab the moisture from wherever it is. Once the thing has had all the moisture from the top it'll slurp it up from the bottom??

Non?

 

[Guest]

Re: how much water should they produce?

ooh no, apparently not. The wet stuff will be fine lurking at the bottom, and the machine will wirr away at the damp air at the top, which once dried will stay towards the top. You either need a very large spoon to stir it all about the saloon, praps better to put it a bit lower down.

 

[robp]

Re: how much water should they produce?

I'd better get that float switch fitted then. What'll happen to all the water at the top??? Did Gerrard Hoffnung write this?

 

[Guest]

Re: how much water should they produce?

Ah, the mositure at the top of the saloon will move down to replace the removed moisture at the bottom. The dried out air from de-hum. will be lighter, so rises to the top of the saloon. I sometimes do quick gravity check from top of saloon steps, and always fall in the same direction (downwards) as the heavier damp air will fall.

 

[robp]

Re: how much water should they produce?

I've gone home..

Why do you get mositure at the top and moisture at the bottom?

 

[Guest]

Re: how much water should they produce?

And then you get clouds forming and an area of low pressure moving in normally from the west except this weekend it seems to have decided it's going to change direction and then it starts raining once the low's passed and the moisture hits the bottom surfaces hence it's damper lower down. Seems logical to me. Pass the Sanatogen please.

 

[Guest]

Re: Pythonesque

I have rarely enjoyed such a bulletin thread. Still chuckling as I write.
Definite Pythonesque (this parrot is dead) and Hoffnung (rising and falling levels).
Thank you for the entertainment .
Co-incidentally it was also useful.