Drippy Cave Syndrome

[Schuster]

Hi all,
I am not a C-Dory owner yet but am trying to find a 25' so if you know someone who is getting ready to part with theirs Im all ears.
Now one comment I read is that C-dorys are known for drippy cabin syndrome. Is there a solution for this? Can the inside of the cabin be painted with a moisture block or felt be applied to the bulkheads or overhead?
Thanks
Dave Schuler

 

[robhwa]

Hi all,
I am not a C-Dory owner yet but am trying to find a 25' so if you know someone who is getting ready to part with theirs Im all ears.
Now one comment I read is that C-dorys are known for drippy cabin syndrome. Is there a solution for this? Can the inside of the cabin be painted with a moisture block or felt be applied to the bulkheads or overhead?
Thanks
Dave Schuler

Key is understanding the difference between TOTAL and RELATIVE humidity. Total humidity is water dissolved into the air. Relative humidity is what you feel, and related to the ability of water to dissolve into or precipitate, out of the air, onto you, your windows, and your cabin interior.

The figure below shows temperature and the total amount of water that can be dissolved into air before it starts to precipitate out of the water (100% relative humidity). Water can also condense onto colder surfaces in the cabin, and then drip from them, which is what you are trying to avoid. C-Dories are bad because their simple cabin construction and large, single-paned windows, allow the interior to cool...just touch a window or wall on a cold day.



Drippy C-Dory cabins (particularly in the PNW) are caused by water in cabin air having higher total humidity than the temperature of air can hold. Heating air in your cabin without exchanging cabin with outside air only reduces relative humidity, not total, and only temporarily. When that air cools, water can condense from it.

What you need is to either remove humidity (I use a 12 volt dehumidifier), or bring in some outside air, which will typically have a low total humidity, and thus, when heated, a much lower relative humidity. For instance, if you bring in outside air at 40 F, 100% relative humidity and heat it to 60 F, the relative humidity will be about 50%. This will mix with and dry humid cabin air.

Sealing up your cabin nearly air-tight, which is a C-Dory feature many small boats don't have, doesn't work, as we are constantly adding water to the air by breathing, perspiring, and sometimes cooking. LP heaters (i.e. "Buddy" heaters) that don't exhaust to the outside also add water as a combustion product.

The Wallas heater is better, as it takes in cabin air for combustion, and then exhausts it outside. Outside air comes in to replace it, and when heated, dries your cabin because it will likely have lower total humidity.

I keep my Wallas on almost all of the time I am in the cabin. This works. Colder, outside air in the PNW seems wet, as it is usually near 100% relative humidity, but when heated, even a little, will typically be much lower in relative humidity, and when this heated, outside air is mixed with cabin air, will likely dry your cabin.

 

[tsturm]

Hi all,
I am not a C-Dory owner yet but am trying to find a 25' so if you know someone who is getting ready to part with theirs Im all ears.
Now one comment I read is that C-dorys are known for drippy cabin syndrome. Is there a solution for this? Can the inside of the cabin be painted with a moisture block or felt be applied to the bulkheads or overhead?
Thanks
Dave Schuler

Any Boat period. :thup

 

[colbysmith]

I've tried fans, my webasto heater, bringing combustion air from inside the boat thereby drawing fresh air into the cabin from outside, solar fans, etc. The boats condensate. The colder it is outside, the more it condensates on the inside. I gave up. I just keep one of those body shammies, the ones used for sports to stay cool, nearby, and mop the hull and ceiling up when I need to. (Usually in the morning after getting up.) Colby

 

[Salmon Fisher]

We found that leaving the hatch in the v berth cracked open and the side windows in the cabin, too, helped keep condensation down when sleeping at night.

If we leave the boat totally closed up you cannot help but get condensation.

During the daytime, wallas heater or furnace on and a window cracked will result in no condensation, in our experience.

There have been a few owners who have either glued on a liner, available through Sailrite. Here's a link to their youtube channel that shows how. I know a couple of C-Brats have done this and it's worked out well.

https://www.youtube.com/watch?v=iMQlTZw2Gu0

Another route is to spray on a liner, kind of thickened sound deadening paint.
If you look it up, you'll find it on C-Brats.

Good luck!

 

[Salmon Fisher]

We found that leaving the hatch in the v berth cracked open and the side windows in the cabin, too, helped keep condensation down when sleeping at night.

If we leave the boat totally closed up you cannot help but get condensation.

During the daytime, wallas heater or furnace on and a window cracked will result in no condensation, in our experience.

There have been a few owners who have either glued on a liner, available through Sailrite. Here's a link to their youtube channel that shows how. I know a couple of C-Brats have done this and it's worked out well.

https://www.youtube.com/watch?v=iMQlTZw2Gu0

Another route is to spray on a liner, kind of thickened sound deadening paint.
If you look it up, you'll find it on C-Brats.

Good luck!

 

[Robert H. Wilkinson]

I know a couple of C-Brats have done this and it's worked out well.
https://www.youtube.com/watch?v=iMQlTZw2Gu0

Our non Cdory boat has something like this in the cuddy. I think it is sometimes referred to as "monkey fur". We have never had problems with condensation in V birth. Not a pilothouse though - camper top which we purposely do not close up tight. May also be the climate of our area.

Rob

 

[bridma]

Install port and starboard portholes in the v-berth. Crack them open when needed. Goes a long way to keeping condensation down.

Martin.

 

[robhwa]

Is anyone else using a dehumidifier while underway? Each person in the cabin is continually adding water through perspiration. Any cooking or boiling (I like coffee) also adds water. I find my DC dehumidifier removes about a pint of water a day, sometimes less, sometimes a lot more. A dehumidifier is probably not necessary, particularly if you are heating the cabin and exchanging air, but I have no problems with a wet cabin, even when I sleep at night, when I keep the dehumidifier going.

 

[ssobol]

I would think that with the "monkey fur" but not additional insulation, all you'd end up with is wet monkey fur. The stuff in the video is probably acrylic fabric and would dry fairly quickly, but still.

In my boat in my area, we do get condensation on the interior if it is cold out. You can see it and feel it with a finger, but so far we have not had any problem with dripping.

 

[srbaum]

Dave,
My boat doesn’t have this issue, because the boat’s previous owner installed tile, like this on the overhead.
https://www.lowes.com/pd/Armstrong-Ceil ... es/3068659
You can view it here
: http://www.c-brats.com/modules.php?set_ ... _photo.php and here: http://www.c-brats.com/modules.php?set_ ... _photo.php

 

[South of Heaven]

My boats did that too. Honestly, not a big deal. I like the idea of a shamee. Plus it'll keep the walls clean.

 

[smckean (Tosca)]

Is anyone else using a dehumidifier while underway?

No, but I do use a contractor grade dehumidifier on my boat. I only do it when the boat is on the trailer and under its roof. The point is that each time I do that I extract 3 to 5 gallons of water out of the boat (using a heater at the same time to keep boat interior 70-75°).

So there is moisture in the cabin even if you don't see it. I can really tell the difference too. Although I don't have any water droplets, or even noticeable moisture, the boat still feels remarkably "dry" after a dehumidifier session.....sort of like travelling to Arizona from Seattle. As soon as you step out the plane door, you notice the difference.

 

[CC Rider]

Is anyone else using a dehumidifier while underway?

I'm curious about this, what model do you use? (Assuming it is a 12V unit) Current draw? Anyone else using one while at anchor or underway?

Thanks,
Chris

 

[robhwa]

Is anyone else using a dehumidifier while underway?

I'm curious about this, what model do you use? (Assuming it is a 12V unit) Current draw? Anyone else using one while at anchor or underway?

Thanks,
Chris

This one...

https://www.lowes.com/pd/Pure-Enrichmen ... 1001389040

It is about 6 in wide, 4 in deep, and 12 in high. I bought it originally to protect some installations of monitoring equipment...run with solar and battery power inside of a sealed box. It worked well, but would only hold about a pint of water, and I eventually drilled a hole in the reservoir and fitted a hose through the box to drain continually.

Came with with a 120 AC to 9 VDC converter. That can work if you have an inverter, but I use a 12 to 9 VDC converter instead. Draws 22 watts, pretty much continuously.

One thing I've found is that the unit "ices" up sometimes with high humidity and low temperature. Instructions say it won't work below 65 F, but it does, it just can ice up, and when it does, it quits removing water. In that case, you'll need to cycle on and off to let the ice melt, about an hour on and an hour off does the trick at C-Dory cabin temperatures (for me about 60F). Once the humidity is lower and temperature higher, generally no problem.

It also heats the air a little, not much in a C-Dory, but some in a gun case or inside of an electronic's box. I was told that dehumidifiers are excellent heaters, with usually a 2:1 or higher efficiency advantage over resistance-only heaters. I remember from a few physics and chemistry classes and in my greenhouse courses that when you evaporate a liter of water, you will absorb 540 kcal (big Calories) from the environment, cooling things. Conversely, when you condense a liter of water from the environment (C-Dory cabin), you will put 540 kcal into the environment around your dehumidifier.

 

[Anonymous]

I painted the interior with ceramic microspheres mixed into an oil-based enamel. It made a significant difference. When I touched the inside fiberglass wall my hand didn't feel a cold surface. I put on two coats and was impressed. I did the same to my wife's sailboat and that ended the drips.

 

[localboy]

http://www.c-brats.com/viewtopic.php?t=1629&highlight=insulation+spray

Above is an old thread about a spray on or roll on insulation, much like Tom just mentioned. I have always intended on doing this, but it's such a big job that I haven't. I work...a lot.

We do find that having a solar exhaust fan installed in the ceiling of the head helps cut down on condensation and dries the wet head out after showering. I installed a Marinco day/night unit. Runs on solar during the day and charges the battery for night use. Finally replaced the original one last summer.

When we sleep we tie the door to the head open all night. Cracking the hatch above the berth allows fresh air in and the fan pulls cabin air out. So far it has worked pretty well. Is it perfect? No. Sometimes we still have moisture on the walls of the V berth etc, but we don't have dripping on our faces when we awaken.

I must say on a side note, the new model Marinco feels really cheap and flimsy compared to the older unit we had. But that model is NLA.

 

[hardee]

Sandy said:

"No, but I do use a contractor grade dehumidifier on my boat. I only do it when the boat is on the trailer and under its roof. The point is that each time I do that I extract 3 to 5 gallons of water out of the boat (using a heater at the same time to keep boat interior 70-75°).... the boat still feels remarkably "dry" after a dehumidifier session....."

I'm curious, how long does it take to do a "session"? And after that session, and you keep running the dehumidifier, how much water do you get on the second session, or third?. I'm just wondering, how do you keep outside air from contributing to that "3-5 gallon" total? Considering the outside air humidity, how long would it take to get the same amount of condensate if you ran that dehumidifier outside, say on the back porch?

robhwa said:

"Is anyone else using a dehumidifier while underway? Each person in the cabin is continually adding water through perspiration. Any cooking or boiling (I like coffee) also adds water."

At typical C-Dory Cabin temperatures, (say 75*F or less), the incipient moisture loss from humans is going to be much greater via respiration than perspiration, unless of course, there is considerable strenuous exercise going on. Typical water loss via respiration is about 1/2 liter in 12 hours, or a liter in 24 hours. 2 people on board over 24 hours is near a gallon. Keeping some ventilation going lets most of that out to equalize with the ambient humidity level. Closing everything up for the night and that half gallon has to go someplace, like walls and ceiling, vent covers and windows, I guess :shock:

Harvey
SleepyC :moon

 

[robhwa]

I'm curious, how long does it take to do a "session"? And after that session, and you keep running the dehumidifier, how much water do you get on the second session, or third?. I'm just wondering, how do you keep outside air from contributing to that "3-5 gallon" total? Considering the outside air humidity, how long would it take to get the same amount of condensate if you ran that dehumidifier outside, say on the back porch?

At typical C-Dory Cabin temperatures, (say 75*F or less), the incipient moisture loss from humans is going to be much greater via respiration than perspiration.

A comment on dehumidifiers in the C-Dory cabin. Here on rainy, misty, Anderson Island, dehumidifiers make life possible ; >) in the winter. I keep a large one in the greenhouse, one in the basement, one in the shop, one in the guest house, one in the C-Dory when on the trailer, and one to move around (camper or vehicles). They are all set to shut off at 50% RH. The 12 VDC mini ones don't have a humidity control and I only run them in the camper or boat when underway.

After a wet trip with the C-Dory, the first session might remove a half gallon to a gallon of water. The cabin interior is often dank and smelly at first. It dries quicky, then it really slows down, maybe a half cup a day, probably associated with "leakage" around the doors and windows. It remains at 50% RH inside, which is where I set it. I keep it under cover when on the trailer.

So, with doors and windows closed, the C-Dory seems to be fairly air-tight, but some water does come in. I can imagine it might be more if I didn't have it covered.

Also, yes, water you lose from breathing usually contributes most of your water loss as vapor, and most of your body cooling when not too active. Both breathing and perspiring put gaseous water into the air and raises RH, the source of dripping cave syndrome. BTW; your dog doesn't perspire much...it only has sweat glands on its feet pads. My wife once had our dog shaved so it could be cooler. Doesn't work, and the poor pup nearly died of embarrassment.

 

[localboy]

When I put the boat up for winter I put an oil heater inside the cabin with a plug in adapter that comes on @ 35F. I also put a Caframo Stor-Dry fan/heat unit on full time and stand up any cushions so they have air flow. I wash all the bedding and store them in "space bags" (vacuum bags). So far, so good. No mold or mildew.