Aft cabin condensation!

[beatlebug]

Hi all,
This is my first winter living aboard my 30 ft hunter in Vancouver.
I knew I had been having condensation problems, but yesterday I realized just how bad. I use my aft cabin as storage (because it is so long) so it has my bike, a suitcase and two bins of clothes. In reorganizing and moving things around I found the entire back had HUGE drops of water all along the ceiling. I took the bins and the suitcase out and the bike will be moved into storage today.
The reason why I am posting is I would now like other peoples thoughts on what to do now. I already wiped down the water and although I put my air dryer back there water is collecting again. I am going to pull the mattress in the back up and collect the small puddle which has formed. I thought I would also put my little ceramic heater back there to dry things out. I see no visible mold (except a little on my suitcase which I wiped off), but could mould be happening inside the cushion? It's super rainy here so nothing can go outside to dry. I was looking into getting a dehumidifier, but I am worried it will pop the breaker if run with my heater, and I really don't want to choose between warm and wet or cold and dry... Maybe another air dryer would help?
Other than that I found condensation managable with towels and placing my heater a certain way.
Second part of my question, if a dehumidifier is the way to go I have seen anything from 4 pint to 70. What would work best on my little boat? The 4 pint one in home depot is 50$, seems like a good deal but I want it to do a good job..

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[jackdale]

I would recommend cracking a hatch a bit.

The dehumidifier would really help.

Also get some of the waffle type material (the name escapes me) to put under the mattresses and cushions throughout the boat.. That keep the the moisture off the bottom and encourage a little more circulation.

[Don C L]

DampRid sure works well for me. Amazon, Walmart...etc. You might need 2 or 3 buckets for the aft cabin.

[Paul Elliott]

Hi beatlebug!

When I moved my sailboat up to Friday Harbor from San Francisco I was surprised at all the condensation. I solved the problem with a heater and cabin fans to keep the warm(er) air circulating throughout the cabin.

However, I don't live aboard, which makes my problem much easier to solve (you are exhaling moist air and all that). Others have reported good results with dehumidifiers, and I expect we will hear some recommendations.

Good luck!

[Lizzy Belle]

Originally Posted by beatlebug

In reorganizing and moving things around I found the entire back had HUGE drops of water all along the ceiling.

That's what my V-berth is like right now, and my aft bunk too.

I'm living aboard my 29' polyester boat, and the problem in the V-berth (and I suspect your aft cabin) is that it's not isolated. A thin layer of polyester between the cold air outside and the warmer air in the boat = rain forest

Since I don't want to spent a lot of € on drying my storage area, my mattresses are protected and all the stuff in my V-berth is in plastic containers.

I have a dehumidifier running 24/7 these days, which helps a LOT. Without it, my main cabin would be problematic too, with it it's controllable. I do have protection in place in all the cupboards etc - everywhere where my stuff comes in contact with the hull, cos that'll all get wet.

The main thing to do is ventilate. Crack the hatch(es) open a bit and leave them open.
A fan also helps, as does heating without producing more moisture into the air inside (an electrical heater for instance, as a paraffin heater will add water to the air).
Also, when cooking, open the hatch near the galley a bit further to get rid of as much steam / water as you can.

As to what kind of dehumidifier: check the room size they can handle.
How much water they can hold in the tank is less relevant - unless the number of times you have to empty it is a major concern. Mine holds about 1L I think -- I empty it daily before bed, full or not.

You didn't mention your bed, but your body produces a lot of water too while you sleep. My set-up: electrical blanket, aquamat, mattress.
I use the electrical blanket to keep everything dry - the cheaper option is to put the mattress on it's side during the day and drying by hand.
When it gets really cold, the sides of the bed / mattress would get wet too since it's against the hull - the blanket takes care of that too.

[leftbrainstuff]

Originally Posted by beatlebug

Hi all,
This is my first winter living aboard my 30 ft hunter in Vancouver.
I knew I had been having condensation problems, but yesterday I realized just how bad. I use my aft cabin as storage (because it is so long) so it has my bike, a suitcase and two bins of clothes. In reorganizing and moving things around I found the entire back had HUGE drops of water all along the ceiling. I took the bins and the suitcase out and the bike will be moved into storage today.
The reason why I am posting is I would now like other peoples thoughts on what to do now. I already wiped down the water and although I put my air dryer back there water is collecting again. I am going to pull the mattress in the back up and collect the small puddle which has formed. I thought I would also put my little ceramic heater back there to dry things out. I see no visible mold (except a little on my suitcase which I wiped off), but could mould be happening inside the cushion? It's super rainy here so nothing can go outside to dry. I was looking into getting a dehumidifier, but I am worried it will pop the breaker if run with my heater, and I really don't want to choose between warm and wet or cold and dry... Maybe another air dryer would help?
Other than that I found condensation managable with towels and placing my heater a certain way.
Second part of my question, if a dehumidifier is the way to go I have seen anything from 4 pint to 70. What would work best on my little boat? The 4 pint one in home depot is 50$, seems like a good deal but I want it to do a good job..

Sent from my SGH-I337M using Cruisers Sailing Forum mobile app

Humidity will increase over time until the air becomes saturated then condensation will form once any surface drops below the dew point temp.

You need to change the air in the cabin for less saturated air. Either run a humidifier or vent. A little heat always helps with natural circulation too. A rule of thumb is 5+ air changes per hour up to 20 per hour for living spaces. Humans excrete moisture in our breath

We have 15W strip heaters in the areas that are rarely accessed. These introduce some natural convection and vent into the main living areas. We then wipe, vent and heat as needed.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[a64pilot]

I just got this dehumidifier and it is outstanding, my old one was noisy as all get out, this one sounds like a dorm fridge and a fan, very quiet. I drain it into the bilge or I would be emptying the bucket daily.
I don't live aboard though and don't have any experience with your level of cold.
Amazon.com: Frigidaire FFAD5033R1 Energy Star Dehumidifier with Effortless Humidity Control, 50 pint: Home & Kitchen

But a humidifier will add some heat, they are nothing at all but an air conditioner, the water collects on the cold evaporator and the air is re-heated by the condenser, since energy is being expended, heat is produced. It won't heat a room or anything, but at least it's not cooling.

Oh, and once you get it dry inside it will feel a lot warmer than the same temp with condensing humidity

[Tayana42]

Ventilate, ventilate, ventilate! And create airspace under all mattresses. We use HyperVent. A small oil filled radiator or a ceramic heater will give you enough heat to take the chill off and will add to ventilation as heated air will rise and escape through the ports or hatches you will open a crack, then drier air will enter to replace it. As Lizzy Belle mentioned don't use a heater that burns kero, oil, propane unless it is properly vented outside or it will add to the moisture in the air (and maybe kill you with CO). A dehumidifier will also make a world of difference. I don't know if your electrical system will support both running at once. If it doesn't alternate them. I never leave a heater running (even electric) when I'm asleep or off the boat.


S/V B'Shert

[hellosailor]

A dehumidifier usually is a small chiller unit that relies on being COLDER than the surrounding air. In the winter? Eh, not so sure about that. And it produces water, that has to be collected and drained.


I'd suggest a couple of "goldenrods", which are low-wattage low-temperature heating rods meant mainly to put on a closet floor, but I'm not sure those would make enough heat for you. Might need to back those up with a small ceramic heater, with a thermostat, for the colder days.

[robert644]

I live on the west coast and I have a dehumidifier, and I am very impressed. It's a 30 pint and I have it set on 'comfort level so it isn't always running. I would suggest placing it where it can condition your entire boat and then get a good fan to circulate air through the aft cabin.

It's great that it keeps humidity down throughout the boat, no foggy windows, and no wrinkled books.

[beatlebug]

Thanks for all the help everyone! I am trying the dehumidifier and the inserts to put under the beds. And I think I will be getting another air drier ☺☺

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[Sandero]

You have condensation because the warmer moist cabin air is coming in contact with the cool surfaces and the water is condensing out... like the morning dew.

You need to dehumidify your internal air... add insulation. Shiva has condensation of all the alum windows and hatches in the window when the heat is on.

[Lepke]

You're making most of the moisture, breathing, cooking and showering. You need to change the air and heat with a system that allows changing the air and still keep the boat warm.
I'm 67 and have been doing this in the Pacific NW since I was a teenager. If you have a diesel engine, a diesel stove works best. You already have the fuel on board. Also, a diesel fired hot water system works good, too.
Besides being dangerous, propane, if unvented, creates moisture as a byproduct of combustion. Unless you get electricity free, it's usually the most expensive way to heat.
If you buy a dehumidifier, buy one that works in cold air, 50+ pints. About $150+ on ebay.

[witchcraft]

You will likely require more than one thing to resolve the issue. Something beneath your matress that promotes air flow, ventilation in general, ( small computer fans can move air around) , insulation and a product like damp rid if you cannot manage the larger possibly power hungry dehumidifier.
Good luck and let us know how it all turns out for you.

[Rick Engelen]

Originally Posted by Sandero

You have condensation because the warmer moist cabin air is coming in contact with the cool surfaces and the water is condensing out... like the morning dew.

You need to dehumidify your internal air... add insulation. Shiva has condensation of all the alum windows and hatches in the window when the heat is on.

This is the real problem, you have a cold bridge! The best solution is an isolation with a closed cellstructure. The isolation must be constructed against the skin without any air between. 'Pur' isolation will do, but it has to be with a closed cellstructure.