Mattresses Moisture Argh!

[exMaggieDrum]

I have used Hypervent pads on two boats now, both in the Pacific Northwest where condensation is a big problem, and on one in the tropics. It is a little pricey and it is 3/4" thick which will raise the mattress that much. But it works really well. It is very stiff and will not crush, or at least, it never crushed after 4 liveaboard years.

http://hyperventonline.com/

[sparrowhawk1]

Well I already mentioned using a cheap heating pad underneath the mattress. If I was somewhere cold I would drop the 120 for this.
Watch video for full review and Amazon link. It's actually $113 and change. When checking the link out I noticed that there are a lot of car seat heaters for between 20 and fifty bucks and they only use about 50 Watts

[senormechanico]

Whether you use a 12 volt or a 120 volt blanket, the energy you get will still take the same amount of juice to produce the heat.
Actually, a 120 volt unit will use more battery because of the efficiency loss from your inverter.
If the inverter was under your berth, you could capture at least a part of that heat given off...
We have a Froli Sleep System and like it a lot.
We previously had hypervent and it worked, but when we replaced the foam mattress, we decided on the Froli as well.

[thinwater]

I find this thread hard to understand in the sense that the answer is obvious and we are avoiding it.

If you laid a mattress on the floor at home and slept on it, would it get wet underneath? lots of people do world wide. It would not.

I lived on my last boat for a bit. Never a problem, even in very cold waether.

The answer in both cases is the same. Condensation requires a cold surface. The floor at home is warm. The bunk in my last boat was insulated underneath.

You don't need ventilation. That can even make it worse. You need to bond insulation to the cold surface until it isn't cold anymore. So easy. It will take about 1-inch, depending on the climate and the boat. It will even make the bed warmer.

[HankOnthewater]

Ventilation and insulation, repeat this 5 times, solves the issue of condenation.
Heating certainly will work as well, but could be masking the problem (lack of ventilation and insulation).
I use at the moment Froli as here: https://froli-systems.myshopify.com/...r-sleep-system
Works very well.

[Pegu Club]

Originally Posted by HankOnthewater

Ventilation and insulation, repeat this 5 times, solves the issue of condenation.
Heating certainly will work as well, but could be masking the problem (lack of ventilation and insulation).
I use at the moment Froli as here: https://froli-systems.myshopify.com/...r-sleep-system
Works very well.

This.
We use the froli system as well works great for under mattress ventilation, plus it adds more cushion under your body.

[john61ct]

For new builds or renovations

Greenhouse benches, plastic grids, just need support at the edges, either 18" or 2' wide, easily cut to whatever horizontal shapes.



Much lighter than ply, bear very heavy loads, maximum ventilation with the space below.

Which may of course may no suit all boats.

[SailingUla]

We have lived aboard for 2 years. 1st we just had dry mat under our mattress, which kept the mattress dry but there was always condensation under the dry mat. Our cheap solution was to buy bed slats from Ikea and cut them to size for our V berth. So no we have the slats, with dry mat on top and then the mattress. Since doing this we’ve had temperatures up to 30 degrees C in the boat with high humidity and there has been zero moisture.

[Meanderthal]

Followup on an earlier post of mine in this thread: we mostly finished insulating under the vberth. It worked extremely well. I'd say 75% reduction in moisture without other interventions. There were spots we couldn't reach behind the hull liner at the foot of the bed, source of the remaining 25%.

@wrwakefield, great point on the polarfleece liner--warm even when wet is a good characteristic in a bedding material for remote and cold places!

[ProteusRising]

Originally Posted by Mike Banks

Not only does one need the ventillation under the mattress--one also needs to drill holes in the side of the retaining board alongside the drainage material so that air can pump in and out as one shifts position. One can also ventillate under the bunks, cupboards etc via a small fan such as a computer cooling fan and allow the air to escape through the screened holes you need to drill. One can glue mesh over these holes if one has other pests aboard--otherwise one has just provided the cockroach hilton.

It is always a good idea in the Land of Oz to have reasonably fresh "nest kill" type cockroach baits aboard--and another deterrent to the pests is borax sprinkled around the place and in the bilges. Putting some borax under the bunks ventillation matting might be a good idea too--it lasts indefinitely, and can be vacuumed up easily.

I like this idea, but am wondering if there might be any negative environmental impact to that borax getting out in the waters where we sail?

[Sailmonkey]

Originally Posted by ProteusRising

I like this idea, but am wondering if there might be any negative environmental impact to that borax getting out in the waters where we sail?

It has come from the waters we sail.


https://www.britannica.com/science/b...mical-compound

[Mike Banks]

If you do not care for the Borax--it is pretty harmless stiff in the quantities you would use--try washing soda instead. Roaches hate that too.