Condensation Under V-berth

[Smushy33]

Hi,
I am sure that this has been discussed before, but I was wondering if anyone has some good advice on how to prevent the v berth from getting wet from underneath. I am pretty certain that it's because of condensation and not because of a leak. We have tried leaving all the windows and the hatch open, but it is still wet in the morning.
Is there anything that really helps to prevent it?

[savoir]

The first thing you have to do is make sure that the locker under the berth is both vented and dry. A soggy old anchor line or bunch of lifejackets won't help.

Apart than that, this is the stuff that I use. There are other products that do the same job.

Hypervent Condensation Prevention Matting

[bobconnie]

I've been using 1inch x1/4inch lathe and monel staples under my bunks for years! works fine and is cheap as heck !!

[flagorio]

Dri-dek under mattresses in all berths.

[JPA Cate]

Have used cheap seagrass mats under the cushions: that worked, but Jim didn't like their odor. Now, we bond a thin layer of closed cell foam to the bottom of the cushions, works fine. It is the heat of your bodies and breath that condenses and makes the damp, and of course, local humidity doesn't help you keep dry.....

Ann

[Hudson Force]

Insulation and ventilation seem to be the two strategies most recommended. I prefer insulation on the inner hull surface so that the warmer interior air doesn't have the cold surface for condensation. A third improvement can be a dehumidifier.

[sparrowhawk1]

Originally Posted by bobconnie

I've been using 1inch x1/4inch lathe and monel staples under my bunks for years! works fine and is cheap as heck !!

How much space do you put in between Thanks

[akkebeng]

Moisture from your body and breath diffuses down through the mattress during the night and, particularly if there is an uninsulated hull in the compartment under the bunk, condensation inevitably occurs. The most efficient way to prevent this is to prevent the moisture from going into the mattress at all. Last summer, we experimentally glued a polythene foil to the top and sides of he mattress on one side of the v-birth, leaving the other unchanged. The difference was dramatic.
The underside of the so treated mattres always were bone dry, even towards the end of the boating season when the water temperature begins to fall.

[Hudson Force]

Your location makes a huge difference in what might do best for a solution. If your sitting in water much colder than the air or if your heating your cabin in the cold north, then you need all the tricks. If you remain in moderate temperatures (water and air) then the simple fixes all work well.

[model 10]

Froli Sleep System works really well. Extra bonus, you get a nice little motion from your bed..

[Cheechako]

as mentioned you need to get the mattress up off the board. Plastic imitation cedar lattice (Lowes), DriDek tiles etc will work. You need ventilation too though. On one boat I made dozens of holes in the V berth plywood covers with a hole saw. Then I made a small teak door to open up the V berth access to allow ventilation. Your body heat creates a lot of water.

[savoir]

If the lockers under the v berth are not vented then louvre vents can help. They come in all shapes and sizes and do a great job. Here are a few.

Sea-Dog : Quality Marine, Industrial and Rigging Hardware

[akkebeng]

The only disadvantage with the foil was a slight crackle when you turned over. Less than we initially feared though. Closed cell foam on top would be even better. We also initially feared that the plastic under the mattress cover would feel clammy but it never did.

If you have moisture in the locker you more probably have a leak or an open path for moist warm air to reach a cold surface. Might then be an advantage if you could funnel that water into the bilge.

Condensation under the cushions in the v-berth works exactly the same way even in warmer climates than our home waters. The water is seldom warmer than the air anywhere on Earth and if, the humidity and condensation is an even greater problem. The v-berth cushions on a friends boat we had the pleasure to sail in the Caribean almost got moldy. You had to raise them on edge over the day to dry out and each morning, they were wet again just from moisture exuded from us. (No, we don't have any problem with incontinence, thank you.)

[Smushy33]

Thank you everyone for your quick replies