de-humidification

What does everyone use for de-humidification? I am trying to seal everything up and I would like to add some additional backup.

Anybody have the answer to dehumidification??

What kind of answer? Do you have a problem now and if so what? If just for general questions then it will help keep the boat interior drier but like all tools it may not be a cure all if there is another underlying problem.

Some info from you about what you are wondering should help get a better answer.

Dehumidifier


Not being a smart ass. When it's cold out and heater on (Alaska) humidity would go up and boat (especially below) would get "sticky" When on shore power or GenSet I would run a dehumidifier...just one I bought in Home Depot/Lowes...made a difference.

I have found after I’m hauled out and shrink wrapped I take a dehumidifier to the boat and run in for a week or so with the drain hose stuck down the opened strainer and out the thruhull. Completely removes the moisture. As I visit the boat I plug it in occasionally to keep humidity down.

It’s nice to not have mold growing over the winter.

You have two posts with almost the same question but a hair more detail.

"Seal everything up" may be a mistake. That is often an open invitation to mildew and moisture problems. You cannot stop moisture from entering a boat. The humidity level will get higher and higher because it will breathe and the moisture will be trapped. No, it will not get out on its own once in.

Protect windows and doors from direct rain and anything else you can but even my full cover has ventilation. We get lots of rain in the winter.

Provide ventilation somehow. Use fans inside to force circulation. I use two small fans set into windows that push air outside to change air from inside.
I also use many other small fans to force circulation around the interior and out of some areas such as the Vberth so they are not isolated.

I use two small dehumidifiers, one in the galley to look after the salon, one in the head to look after the fwd. part. THey are on timers as they can freeze up in cold or freezing weather so cannot be left running all the time, or shouldn't, or they become useless. They also were modified, very easily, to drain into the galley and head sinks so the catch pans are now self draining.
Others use one larger dehumidifier but again they can freeze up. You will need to modify to make many of them self draining into a sink that itself drains.

I learned years ago that even with the dehumidifiers and some fans I could still have damp areas which then mildewed. Once I figured out to force circulation the mildew disappeared.
Getting down to the boat , or a trusted friend, to check regularly will help.

The dehumidifiers are only one tool to help.

The fans a small, 3" muffin or computer types of about 10watts each so a lot of them do a good job without running the power bill way up. I simply mount them on a piece of plywood and set them around in a manner to move air.

Any more specific questions , then ask, but please a bit of detail about what you requesting.

Drago said:

Anybody have the answer to dehumidification??

Click to expand...

Yes.

After trying the “Damp Rid” and the small dehumidifier, we switched to this one. This thing really sucks the moisture out. And since we are heading south next year and humidity is pretty high down south, we needed a solution.
Done!

We use a few Davis Air Dryrs (sic), along with one 1000w electric space heater on a thermostat for heat. We have no moisture issues.

We have 2 dorade vents open, and 4 engine room vents that are covered with sunbrella so some air passes. I usually leave the engine room door open to the cabin.

This is going to be location and boat specific. Down here in the sweatbelt, when not aboard, I placed a fan (carpet dryer) set in the v-berth that gives slight but sensible air movement all the way to the aft cabin. Runs on low speed perpetually. Zero condensation and/or mold issues. Summer and winter. Down here the dank cooler months are the major challenge. A little air circulation goes a long way. Might try that first.

Here in Panama City area, you will be one sorry person if you walked off and left a boat closed up for an extended time, summer or winter. I cannot do too much about the bridge deck are of my downeast style boat other than go out every three months or some and use Tilex mold root killer and a rag to wipe away the new mold. To protect the faux leather upholstery and vinyl overhead and all other surfaces I employ a very small Walmart Peltier effect dehumidifier 24/7/365 which seems to do a good job. All cabinets and doors are opened, and I drilled a hole in the bottom of the quart-sized bucket of the dehumidifier, glued a few feet of small clear vinyl hose into it and put the end in the galley sink to drain. On my wooden trawler, I used the largest freon-coolant dehumidifier I could strap onto the forward head vanity and set it up the drain through the sink, again 24/7/365. I am thinking for somebody in the PNW witha minor winter heating bit of humidity one of the larger Peltier effect units would work. What have you got to lose for a mere 40-50 bucks?

rgano said:

Here in Panama City area, you will be one sorry person if you walked off and left a boat closed up for an extended time, summer or winter. I cannot do too much about the bridge deck are of my downeast style boat other than go out every three months or some and use Tilex mold root killer and a rag to wipe away the new mold. To protect the faux leather upholstery and vinyl overhead and all other surfaces I employ a very small Walmart Peltier effect dehumidifier 24/7/365 which seems to do a good job. All cabinets and doors are opened, and I drilled a hole in the bottom of the quart-sized bucket of the dehumidifier, glued a few feet of small clear vinyl hose into it and put the end in the galley sink to drain. On my wooden trawler, I used the largest freon-coolant dehumidifier I could strap onto the forward head vanity and set it up the drain through the sink, again 24/7/365. I am thinking for somebody in the PNW witha minor winter heating bit of humidity one of the larger Peltier effect units would work. What have you got to lose for a mere 40-50 bucks?

Click to expand...

That’s exactly what I did. I had a terrible problem with mildew on Possum. I bought one of the little Peltier Effect dehumidifiers, plugged it in, ran a drain hose to the sink and the humidity dropped down to about 60%. That cured the mildew problem. https://www.amazon.com/Eva-dry-Edv-...ocphy=9052029&hvtargid=pla-305170695489&psc=1

Pick up a cheap hygrometer so you can keep track of the humidity.
https://www.amazon.com/Habor-Hygrom...ocphy=9052029&hvtargid=pla-350015890685&psc=1

For whatever reason, I had a very big problem on my Mainship Pilot. I listed it with a broker and he had a showing and I get a call with...."What in the hell is wrong with yhour boat"??? I go down there and the inside of my boat is GREEN!!!!!!! After a good cleaning and placing a smallish dehumidifier in the galley sink, everything was fine. And those people that saw it in its green state still bought it!!!

So A dhumidier I bought from amazon!!!! I still have it and use it on occasion!!

I have a dehumidifier for both the main salon and the foreward cabin.

Real dehumidifers bought at Home Depot for a couple hundred dollars each.

I set the humidity at 55% and the boat is nice and dry...no clamminess, no condensation, just a nice dry boat.

One of the best boat investments i ever made.

Use a 30 pint compressor type of dehumidifier draining into a sink drain. Add few fans to keep the air circulating. Run it 24/7.

I acquired one of these
http://www.ebacusa.com/hvac/CD30.html

I put it next to the galley sink in the winter. Has made a tremendous difference.

Boatyards take all sorts of gizmos off boats when they are being sold. I got this one for free. I was going to buy a cheap one, so I don’t have a comparison and can only say that this thing really really works.

Boring old house dehumidifier, bought on sale, with the hose attachment option, which most seem to be coming with now...


sits carelessly on the counter, short hose into the kitchen sink, while docked in a sheltered marina.



Perhaps something more purposeful in an installation, when I get a round tuit and all the other imagined renovations...?


Does the job, and this time of year, puts just as many heat BTU into the boat as amps it consumes. AC takes care of most summer time moisture.


RB

I've used the Mermaid Manufacturing Dry-Pal on my last two boats and have been very satisfied. I plan to permanently install one under the settee of my current boat. It uses 1/3 the power of my A/C and keeps the interior humidity between 35-45%. It does generate heat and some noise, so it is only used when the boat is not occupied. Otherwise, A/C or lots of fresh air.

I've posted this before, but...my Cruisair units have a dehumidification setting. You hold three buttons on the thermostat panel at once to activate.

The default setting is that the unit runs for 30 minutes, regardless of temperature, twice a day. You can adjust for more operating time if needed.

The default setting is all that I've needed in coastal NC, which is a relatively humid location. There's no need to deal with another piece of mechanical equipment, and the fan on the a/c unit circulates cabin air as the system is running.

The worst mold problems in my area occur in the spring. Relative humidity is high, but air temp is not. Interior surfaces of the boat are cool (below dew point), and moisture condenses on those surfaces. That's what produces mold.

So, just running the a/c may not take care of high humidity in the spring, unless you run the a/c at very low temperatures. The dehumidifier setting runs even when ambient temp is low.

We store in FL for 6 summer months.

We are NOT aboard during the storage.

Tried many solutions and a rotary vent as seen on rooftops seems to work to return to a non green slime interior.

The Dorades let air in , the vent pulls it out.

https://www.ebay.com/itm/173490894310

Purchase an aluminum unit with SS bearings.

Vent from the furthest point in the hull or cabin to get all the moisture.

FF said:

We store in FL for 6 summer months.

We are NOT aboard during the storage.

Tried many solutions and a rotary vent as seen on rooftops seems to work to return to a non green slime interior.

The Dorades let air in , the vent pulls it out.

https://www.ebay.com/itm/173490894310

Purchase an aluminum unit with SS bearings.

Vent from the furthest point in the hull or cabin to get all the moisture.

Click to expand...

I was pretty sure Dorades are vents but since I am not familiar with the name I searched for it on google images. I am sharing what I found. Not what I expected for improving air quality.

Drago said:

What does everyone use for de-humidification? I am trying to seal everything up and I would like to add some additional backup.

Click to expand...

Drago said:

Anybody have the answer to dehumidification??

Click to expand...

These first two posts were 11 minutes apart. What's the hurry?

At HopCar's recommendation, I purchased an Eva-Dry 2200. It's the larger size than HopCar posted but I did the same as Parks by adding a drain hose to drain in the galley sink. It runs when I'm not aboard during our damp seasons fall-spring and does a great job of keeping the humidity low. I monitor this via my onboard Accurite weather station that displays indoor and outdoor humidity.

It's quiet, 120VAC and very efficient. I have no complaints.

In the PNW, the worst time of the year is from Sept-Nov. After that time, the the humidity drops as if the temperature inside the boat is higher than outside. We use a 500 watt dehumidifier. That together with a couple of heaters on the low setting and the humidity remains at ~50%. If very cold outside, I turn the dehumidifier off.

Drago said:

What does everyone use for de-humidification? I am trying to seal everything up and I would like to add some additional backup.

Click to expand...

We use a 30 pint GE dehumidifier that we got at Home Depot. We pull about 30 pints out every 12-24 hours.

https://en.wikipedia.org/wiki/Dorade_box

On our 90/90 as full time livaboards we use a pair 6 inch screw in plastic covers on the thru deck stand pipe.

Should the Dorade box be damaged one inside and one outside keeps the water out.

The pipe can be filled with insulation for winter living.

In the summer heat a pair of spare covers can be purchased , and 12v or 24v computer fans installed .

These only work in one direction so if you want the vents to blow or suck, it will take a pair.

Similar units vent the galley.

The 24v have almost zero noise on 12v and a very light action.

Drago said:

What does everyone use for de-humidification? I am trying to seal everything up and I would like to add some additional backup.

Click to expand...

Just saw this (see, those Trawler Forum newsletter emails work!). We liveaboard 24/7/365 in the Pacific NW and think of dehumidification in terms of water vapor, mold, and mildew. Because one will lead to the other. Here's what we do to keep condensation, mold, and mildew at bay...

1. One large household sized dehumidifier aft (purchased at Home Depot) and one Eva-Dry 2200 forward. They run an average of 6-8 hours a day. We've had the large one for 5 years and just bought the Eva-Dry a couple months ago.

2. Kanberra Gel ALL OVER the boat. We've been using it for 6 years. It is Australian Tea Tree oil that evaporates into the air and kills mold spores and even bacteria. My wife also uses the wipes and soap. I use the spray - mostly in the head!

3. H2Out Space Dryers. We have approximately 15 in places throughout the boat. Much better than those Dri-Z-Airs that use chemicals as there's no caustic liquid to dispose of. Plus you can recharge them in a conventional oven. We've been using them for 6 years as well.

4. Plastic sheeting on the large main cabin windows, the kind you use a hair dryer on to make taut. We call this our Beverly Hillbilly's approach, but it really helps to retain heat and keep condensation off the windows all winter.

5. Our Wallas diesel forced air heater pretty much runs from, well, now (just turned it on yesterday) through next May. Keeps below decks warm and comfortable on a low setting, burning under a gallon per 24 hours.

Of course, we have a 46-foot double-decked trawler with a LOT of cubic volume for the size, so your needs may vary. But we will continue to do these things as they make a real difference. If you or anyone is interested, we also sell Kanberra Gel and H2Out products in our online store.

A couple of Davis Air Dryers do the trick during the summer. 6-8 Containers of Damp rid once it is pulled. Although I suspect this is a trick question as it will depend on where you keep the boat, its size and design.

Word of caution when you have a wooden boat : I put an electric dehumidifier on board and obviously as I found out later, had it run too long. Nice dry boat, but also planks in hull shrunk due to dryness........boat is under cover now and far less moisture.......

We're planning to try a hygroscopic, calcium chloride (50 lbs. total), in mesh bags hanging over four sinks: both heads and both basins in the galley.



She'll be covered in Indiantown FL next summer, which will keep the rain out (if not blown away by a hurricane). I'll post the results next December.

I keep my boat in a warm climate year around. About five years ago I started using a Caframo Stor-Dry 9406 Warm Air Circulator, 120V AC. In my last boats cabin, a 29 ft cruiser. It worked great. I now have a 33 ft trawler with much larger cabin volume. So now I have a total of 3 . One in the bow area, mid wheel house, and one in the aft galley area. I run them when ever the boat is closed up not in use for more than over night.
No drains to worry about and they use very little power. I not sure how well they would work in cold winter storage.