how do you prevent moisture build up in your storage hatches?

[bowman316]

I have a 26 ft Grampain sailboat, and it has several storage hatches inder beds and benches. The bottom of these hatches in the hull, so the water is right on the other side.
I constantly get condensation and moisture build up inside these hatches, AND on the bottoms of the cushions that cover the hatches.

Would drilling a small hole or 2 into the sides of the hatches help? so that they could vent out into the main galley?

This has been plaguing me for years. I buy those cups of moisture absorber at walmart, but they quickly fill up with water, and are ruined. or the tip over, and spill.

I now have mold on the bottoms of my new cushions that I made last year. The bottom is plywood.

 

[smokeonthewater]

Re: how do you prevent moisture build up in your storage hatches?

My first thought is that maybe your windows are leaking. Condensation on the bottom from the cold water on the outside should stay condensed and drain to the bilge where it is pumped out....

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

but that's the thing, these hatches don't drain into the bilge. they are completley glassed off from the bilge. the bilge is in the center of the galley, below the floor boards. and the hatches in question are on either side of the bilge, as the hull rises up from the keel.

wouldn't drilling vent holes on the interrior sides of the hatches help less condensation build up? even if it drianed to the bilge, wouldn't the condensation the the inside of the fiberglass cause mold? i might try putting baby powder inbetween the cushions and the fiberglass. to keep it dry.

 

[smokeonthewater]

Re: how do you prevent moisture build up in your storage hatches?

drilling ventilation holed will allow more humid air to enter the space.... It just seems very unlikely to me that you are getting more than a few drops of water out of the air trapped in a small enclosed space

Look very closely for signs of leaks from above.... My boat also has enclosed compartments like you describe and while they ARE able to drain, they stay absolutely bone dry without ventilation.... IMHO unless you are living on the boat and keeping it heated in near freezing water there just isn't gonna be THAT much water pulled out of the air alone

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

Isn't it like a glass of ice water condensating?
Does the water on the outside of the hull, condensate thru the hull, and into the hatches?

or, maybe its the inch of standing water in the bottom of the bilge, that is condensating into em. cuz some may be vented to the bilge.

I just can not pump every last drop of water out of my bilge, cuz the pump sucks air. there is no drop down, its just an 8 ft long pan, where the water spreads out. (poor design)

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

here is a pic of the worst of the mold. some of it is even hairy and 3d instead of just flat.


I have had small leaks where rain water will get it in the galley roof. And the windows. I have calked A LOT on the roof and windows. But the rainwater leaks might get the walls wet, or possibly drip onto the cushions, but they would not get into the hatches.
I guess if the leak were bad enough it would, but these small leaks are all absorbed by the wood and stuff before the water can run down into the hatches.


where i sleep, is directly underneath a flat sufrace on the bow, and I have noticed that on days where it rains constantly for 24 hours straight, that water just condensates thru the fiberglass. a small ammount. It is not leaking. I DO have a few small leaks, im talking just a slow drip when it is downpouring outside.

 

[jigngrub]

Re: how do you prevent moisture build up in your storage hatches?

Look for and try a product called Damp Rid, its basically just calcium chloride in a ventilated container and the CC absorbs moisture. You can put these containers in your hatches and it may help with your moisture problem.

I'm thinking your problem may be more extensive than youwould like to think or admit and you have water saturation and intrusion problems with your boat.

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

So I realized that most of the compartments do drain into the bilge. the bilge has always had an inch of standing water in it. I just cant pump it out without sucking air. and there is no plug or any gravity drain.
Could the bilge water be the source of all the condensation?

 

[dingbat]

Re: how do you prevent moisture build up in your storage hatches?

The source of your condensation is the constant 90-100% humidity in Maryland and a lack of air circulation in the areas where it is a problem.

My boat is stored inside the equipment shed over the winter. I leave all the hatches and windows open and the cushions thrown about the cabin to let air circulated around them. Even then, I still get some mold here and there. Some years more than others.

If I do not wash the salt spray off everything at the end of the season, I end up with a science experiment no matter what I do. I assume that the “salt” moisture carries enough nutrients to get the “experiment” started no matter how dry you keep things.

FYI: Fiberglas is not permeable. If you have moisture migrating thru the hull, you have much bigger problems to deal with

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

Ok, lets say you have standing water on top of a flat surface. wont some moisture condensate thru, no matter what the material is. I mean even a steel canteen or thermus will condensate

 

[smokeonthewater]

Re: how do you prevent moisture build up in your storage hatches?

condensation does NOT pass through the surface... It is drawn out of warm humid air from contact with a cold surface (cooled by the water below)

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

So either this boat has a stupid design, or a previous owner laid some new fiberglass, and jacked up the drainage system.
I have a locker in the galley, just to the port of the floorboards and bilge. This locker comes down to a tiny point where the hull meets the keel and bilge. But there was standing water in there. The water was right on the other side of the bilge, it just had no hole to get thru.

So i drilled a few holes, hoping that I did not drill too low, and go thru the hull.

WHY would you not have all of the lockers drain into a central point?

It gets worse. up under the V-birth in the bow, there is a big locker under there. and this drains into a V shape of the hull. And there IS a hole drilled, allowing this locker to drain into the cavity under the fiberglass deck in the bow. BUT, the front fiberglass deck, is glasses off from the bilge. so there is a huge cavity in the front that was not draining into the bilge.

But this cavity is just, I mean you cant even see where it goes, you just have to use your imagination. I mean there could be 200 gallons of water in this void for all i know. there is no way to find out other than drilling an praying.

 

[Grandad]

Re: how do you prevent moisture build up in your storage hatches?

Once you have good drainage and ventilation (most important), how about lining the below water hull sections within the lockers with a relatively thin but durable insulating material such as 1/2" thick sealed cell foam exercise mats. That might help control some of the condensation problems. - Grandad

 

[Watermann]

Re: how do you prevent moisture build up in your storage hatches?

Interesting problem and of course the gloom and doom scenarios are always nice to read.

I would add some active ventilation to the cabin (blower fans) maybe on a timer like in a bathroom. Also adding the ventilation to the compartments is a good idea but I would take it a step further by doing a cut out that you can add a decorative vent inserts to allow the air movement needed.

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

I wish I could find blueprints for the hull design of my boat. I would love to know what this large void looks like, where the mast connects into the keel. well where the support pole goes from the keel to the roof of the galley.

 

[Grub54891]

Re: how do you prevent moisture build up in your storage hatches?

How about these,you need to vent the interior to get rid of the moisture
Solar Vents & Fans by Discount Marine Supplies
Grub

 

[Watermann]

Re: how do you prevent moisture build up in your storage hatches?

I wish I could find blueprints for the hull design of my boat. I would love to know what this large void looks like, where the mast connects into the keel. well where the support pole goes from the keel to the roof of the galley.

There is some information and photos on this site - GRAMPIAN 26

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

How about these,you need to vent the interior to get rid of the moisture
Solar Vents & Fans by Discount Marine Supplies
Grub

I have that exact fan installed in my roof. I also have a portable solar fan that has a solar pannel that hangs from the window.
But this fan has no power at all.

 

[bowman316]

Re: how do you prevent moisture build up in your storage hatches?

There is some information and photos on this site - GRAMPIAN 26

yea, i have been to that site 100 times. but there is nothing on there to help you understand how to drain the lockers. i wanna know where to drill holes to drian out any trapped water that i cant see.

 

[Yacht Dr.]

Re: how do you prevent moisture build up in your storage hatches?

Try cracking all the floorboards and compartment covers when your not using the boat.

Air movement is key here.