We tried the tiny compact ones (not living aboard, just trying to keep the moisture down) and ultimately they helped, but didn't work. We're now using a 'standard' Sears unit, about 2 feet tall (20l, I think).

With multiple breathing humans on board the majority of the time the load will be greatly increased. I think you'll need a 20/30 pint style, but it will be a bit of a PITA to work around in a liveaboard situation. Despite that, your boat will thank you.

I know all our paper is dry and crisp all winter.. and the boat feels great running a dehu at 50% setting.

 

Is it possible to set a 30pt dehumidifier on a cushion while it is running? How easy would it be for one person to move it from counter to table to floor etc. etc. etc.?

And/or if we made a ledge by covering up our sink in the head - would it still get the water from the kids breathing in the quarter berths? They sleep with their heads toward the back, and our head is right in front of the front V berth where we sleep.

 

Now you say you are "moored" do you have shore power? Dehumidifiers pull a lot of electricity. I don't think you could run one off of batteries. Basically they pull the same amount of AC as a good sized air conditioning unit. If you are at a mooring, I think you will need to look at a very dry source of heat to try to dry the boat out like a bulkhead heater, or a forced air/hydronic furnace.

 

We leave our dehum. running in the head with the doors open and it seems to keep the entire boat 'dry'.. but we don't live aboard. We also don't generally run it when we are aboard, and have noticed the RH below go from 50/60% in the evening to near 80% overnight from two people breathing and the boat closed up. We primarily use it to keep the moisture at bay this time of year.

One thing you might to is find a place (below a table perhaps?) and rig a hose so that it automatically drains into a bilge sump (or on a counter and drain into a sink) so you needn't worry about filling the reservoir.

They are a bit bulky and heavy.. ours weighs about 20 lbs or more, I reckon.. it's a chore to pack it to the car for off season sails...

 

Miata beat me to it. If you are living on the boat I assume (hope) you have some form of heat which should keep the boat dry. What type of heat do you have?

 

We do have shore power. My understanding is that we have two circuits, both at 30 amps of shore power right now. Like I mentioned in the original post - we just moved on a few months ago, this is our first 'fall/winter' and up till two weeks ago the weather was AMAZING.

So anyways - we just put up insulation (the silver supper bubble wrap type stuff) in the roof of the main cabin and the roof and sides of the V berth.

For heat we have been running a West Marine Model 9200 electric space heater that runs on shore power. We have a toaster over, dorm sized fridge, and an electric burner that we plug into shore power to cook with. So far, we have pretty much only been using it on setting '1' while we are awake and at the boat. It seems to be holding up for now, but if anyone has better ideas I am all for it.

We left the boat for about 48 hours and I was amazed by how 'dry' it was when we returned since it had been raining and their was no heat that entire time. I really feel like a big part of our problem is that we have 4 people sleeping full time on the boat - we all have to breath.

Also, if it makes a difference, we only have an outboard motor now, the inboard diesel went bad and was removed by the previous owner.

 

There are two great dehumidifiers, both made by Eva-dry. They're peltier cooler powered(fewer moving part, cheaper but higher power draw).
I use the EDV-1100, the smallest available in my Alberg 30(liveaboard with 2 people/continual construction site and some leaks.) Paid 45$ on amazon, and it's been running 24/7 ever since.
I have considered upgrading to the edv 2200 if I can find the space for it, the water extraction rate is 3-4x better, for 2x the footprint and power draw however at this point I'm not sure if I need it, my RH seems to sit around 50%.

My edv100 draws 2.5 amps.
Positioning makes a big difference, I've tried all over.
It needs:
-warm air, the extraction rate drops by half in cold air.
-space. I had it in a shelf with only about 2" of space over top for a week, I emptied it only once and it wasn't close to full, normally I empty it more regularly and full.

The only modification I've made so far was to remove the fancy grate on top where it exhausts, it moves a lot more air without the grill, and seems to extract a lot more water without it too. On the one hand I was concerned that the air moving faster would mean that it wouldn't spend long enough in contact with the cooling element to dry it, but the increased air movement was a bonus so I figure it evened out. Non-scientifically, I think it fills up less with the grate in, so it was a win in all regards except for being a bit more of a pain to clean some day I guess.
I have considered swapping the fan out for a quieter computer fan, and or looking online to find a very energy efficient peltier cooler, and using a high quality computer heat sink(more surface area) to make a better version of my own.
If I make my own, it will duct the air from cabin top to floor, the warm air at the top has the most moisture, and recirculating warm air to the floor is a very efficient way to make the boat stay warmer longer(you lose heat upwards, so keeping the warmth distributed in the air space helps, and increasing the temperature at the floor level makes the biggest difference in comfort). I would have the warm side of the peltier exposed with a small fan on it as well, this way 100% of the electricity used will be heating the cabin effectively.


I can't recommend one enough. The first month I had it on board I was emptying it all the time, now it fills up so much more slowly.
I had initially planned to have it in the galley and then drill a hole in the tank and let it drain to the sink but since it fills so slowly now I just dump the tank in the head occasionally. You can find ways to stay warm, but damp is much harder to beat.



You can buy the marine version(same specs including energy consumption as the Eva dry models) for close to 1000$, but I figure i can replace my 20x, and with no difference in energy consumption I see no benefit at all to going with the marine model.


The best change I made to my boat was buying those cheap brightly coloured interlocking foam tiles at Home Depot designed for kids play areas. We noticed a difference within an hour, no more cold feet on the floor, and the air around your legs is much nicer when warm.
They have two additional benefits.
1. they essentially seal the bilge off from the cabin, preventing the air/heat/moisture exchange that normally occurs.
2. The bright colours make it much easier to find the small parts when I drop them, and the foam prevents it from going down the holes into the bilge.
.

 

we are also in the PNW and on a 30' live aboard, but there are only 2 of us... we use the Soleusair 30 pt model ($180 through home depot online) and it sits under the dining table to the back of the seating. Yes, it is a little large.. you might have trouble seating all 4 of you at the same time while it is there... and we only run it at night since during the day the entryway is usually open so would be a waste to try and dehumidify the entire outdoors... it pulls 1-3 quarts of water out of the air each night for us.. manual says it uses 420 watts 3.8 amps.

be advised, you don't want this sitting right next to someone trying to sleep, it alternates pushing out warmish to cool air out the top depending if it is dehumidifying or running the fan waiting to pull more water out of the air. Will drive you nuts trying to decide if you are freezing in your sleep or baking

the only place that seems to not stay 100% dry during the night this way is the extreme front end of the V berth where blankets bunch up at our feet... but it is not bad. If you stayed buttoned up more and ran the dehumidifier longer each day it may not be an issue.

 

For those of you who run a dehumidifier on your boat, do you keep your boat as air-tight as possible? If not, don't you worry about trying to dehumidify the outside atmosphere?

 

We close the boat but she has always-open dorade vents. Beyond those we do not leave hatches open in the off season.

When I first got the dehumidifier I thought 'drier is better' and left it on continuous cycle.. after a week of that one of my wooden sliding doors to the head had shrunk enough to fall out of its track... so there is a 'too dry' scenario.

Now we leave it at 50% and things feel dry below all the time. We leave everything below (doors, cupboard doors, seat backs etc) open too so that nothing's really 'isolated'. I'm sure that spot measurements at the extreme bow and aft cabin might show higher RH than in the main salon, but overall the boat feels great all winter long, and we have NO mildew on anything left on board for the winter.

 

I think you may find yourself disappointed if you rely on the 4pt to "maintain" the dryness once you get it down with a larger unit... remember, every time you open the companionway you basically let in all the outside and will be needing to get that water out of the air... again.... like I said before, just overnight we pull more than that out....

I could be wrong.. but I would suggest you go into your experiment with caution and low expectations just in case

 

Where are you located that you pull out more then that overnight? Are you living on it?

I try to have low expectations all the time - makes one happier in general I think

 

I try to have low expectations all the time - makes one happier in general I think

That is a way to a happy life, make goals achievable. (achievable sounds better than low expectations!)

 

I wonder if one of those solar powered vents might help with the moisture problem. With the heat going at night if you had a small ventilating fan going to exhaust the warm, moist air it might help (you could shut if off during the day or when it's really cold out). We don't live aboard but our boat stays dry without a dehumidifier (I turn the fan off in the vent for winter but we have three open dorade vents always open).

 

I have lived aboard in Alaska and the sound for many years. I learned a few things. First you need good air circulation. Don't batten the boat down tight. If you cook with propane increase the circulation while doing so as propane produces h2o. I tried just about every thing and settled on the dryer units. Very low electric use. They circulate the air via convection produce dry warmth,an amazing amount. They are inexpensive and last a long time. Also no elements. i ha e to leave for periods and feel very comfortable with leaving them on. again if your circulation in the boat is good you will be surprised at how dry things will stay. Also bunk mate,placed under the cushions will help with air circulation and keep cushions dry,thus no melded. Hope this helps

 

Just thought I would give an update - we went and purchased the EvaDry 2200 4 pint. The humidity conditions had steadily worsened the few days we at the boat before it arrived. So when I plugged it in at 4 pm today our reader said about 96% humidity in the boat, it was about 52 degrees outside, and raining lightly. We turned it on and left, we came back at 10pm and it had collected about 1/2 cup of water and was at about 90% humidity when we came back. Hoping for lots of water with no increase and preferably a decrease in the morning humidity numbers.

 

I'd think you'd need to get the humidity down to 60% or so, before you start feeling better, and have drier living conditions.

I wonder if that unit can get it down that low with 4 people breathing in there, to say nothing of cooking. Maybe if you combine better ventilation with the dehumidifier?

 

So the numbers in the morning are almost 1 cup or water in the machine, about 87% humidity, which the fact that it went down, not staying the same or up, gives me hope.

 

I've stayed around 60 percent. As an experiment I turned mine off a week ago. I'm over 80 percent again. I think it will take a lot to get the humidity down to start, but keeping it lower is easier.


Jeremy
Sent from my SGH-I747M using Tapatalk

Edit:I had to install a real dehumidifier this week in a boat that leaked. It is pulling an amazing amount of water, 20liters a day I think(3 full tanks).
Totally different, it's pulled the boat down to 60 when combined with a big blower.
Overkill for me, but I might try it in my boat once we're done, just to pull me back down before I turn on the small quiet one again.

 

Edit:I had to install a real dehumidifier this week in a boat that leaked. It is pulling an amazing amount of water, 20liters a day I think(3 full tanks).
Totally different, it's pulled the boat down to 60 when combined with a big blower.
Overkill for me, but I might try it in my boat once we're done, just to pull me back down before I turn on the small quiet one again.

So what kind of dehumidifier is this??? We are going to be going out of town for a few days and I wonder if it would be possible to rent something like this to put in while we are gone? Assuming that it would you know, fit in our hatch, not blow the circuits, and that I could move it by myself. I was thinking of calling the local 'tool rental companies' in town to see if they might have something.

 

This is really encouraging. We have a regular household unit from Home Depot, just two aboard, breathing and cooking and all. Heating the air dries it out some and helps, but still, we often pull out a quart a day in our 33-footer in Maryland.

I'd love it if we could find something more space efficient than our current unit, if it worked.

 

I'd love it if we could find something more space efficient than our current unit, if it worked.

Hunter Marine was installing a Dehumidifier in their higher end boats about 15 years ago. I do not know if was a unit that shared the blower as part of the A/C unit or a stand alone dehumidifier strictly on its own only designed for Hunter. Does anyone know?

 

When I restart my dehumidifier for the fall season it tends to fill up in a week, but 2 weeks like that it seems to go into 'maintenance mode' where the water recovered is much reduced, often going a month before needing to be emptied. We do put a bit of heat on board to prevent the dehu from freezing up.

Keep in mind, everyone, that heat doesn't really 'dry things out' directly.. warm air can actually support more humidity than cool.. it just stays in the air as opposed to condensing. For example warm air against a really cold window really gets to be 'dripping' because of the available moisture in the warm air.

 

Harbor Freight Tools has the inter-locking foam anti-fatigue mats fairly cheap. A pkg of 4 is just $9.99. Black only, though....

 

65 pint from home depot. I'd get the smaller one, this was urgent, and combined with a blower.
I got the premier brand one. 3 reasons over lg. Either will do, both have house fittings to drain to bilge.
1 has a decent handle
2I like that air goes in the front and out the top.
3 double the warranty length.

Rental was the same as buying after a week or two. Never understood adding heat and just moving air around in a sealed boat.


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65 pint from home depot. I'd get the smaller one, this was urgent, and combined with a blower.
I got the premier brand one. 3 reasons over lg. Either will do, both have house fittings to drain to bilge.
1 has a decent handle
2I like that air goes in the front and out the top.
3 double the warranty length.

Rental was the same as buying after a week or two. Never understood adding heat and just moving air around in a sealed boat.

Sent from my SGH-I747M using Tapatalk

In my home and garage I have had 4 or 5 dehumidifiers and I think the warranty is a big issue. It seems to me that the new electronically controlled units are not nearly as reliable. I had an old one that seemed to be work for ever. The newer ones seem to have controllers go out. If I were to buy another one, I would get the extended warranty as I have not seen a new style last more than a year or two. I like the idea of Sears as they actually have service centers locally.

 

I think this is the one a couple of friends put on their boats a few years back - St.St. small size - drains into a sink -

sorry can't remember where they bought them - they both said they shopped around a bit -
Dry Pal Dehumidifier / Dehumidifiers / Marine Division / Home - Mermaid Manufacturing - Home of Mermaid Marine Air Conditioning

 

Seems like you would need multiple units for a boat of any size.

 

How often do you run your de-humidifier? Does it differ on where you are located, if you're docked, out at sea, etc.? It probably depends on where you are, how much humidity is in the air, and if you're living aboard. I did see that you run it at night. My husband and I want to live-aboard, and we're just uncertain how often to turn on the dehumdfyr.

 

Living aboard in the wet season here in the PNW I'd expect you'd want to run it pretty well full time. We leave ours running (non liveaboard) at 50% and it keeps things nicely dry... with two or more people breathing below the load would be higher and I'd expect you'd need to run it steadily... or at least every day if its too noisy at night.

Once the boat is 'dried out' we get very little water in the reservoir even now... but it's different with the moisture from people on board all the time. In the off season the cabin RH will go up to 80 -90% overnight with two of us sleeping and no dehu running....

 

Living aboard a 30'. I keep two small electric (west marine brand) dehumidifiers running full time. I'm tied to a dock with shore power though. When it's dry outside I crack the fwd hatch and open all of the other ones in hopes that air circulation will keep things fresher upon my return. It seems to be working. One dehumidifier is in the V berth, the other I move around near the aft qtr berth or the galley. I was using one but discovered mold/mildew on a couple things stored in the v berth, so that's why one is dedicated just to that space now. There's a little skylight up there that tends to leak if it's raining hard.

 

... I keep two small electric (west marine brand) dehumidifiers running full time....

I find that calling small heaters dehumidifiers is blatant false advertising. I can't respect that.

From Websters:
Definition of DEHUMIDIFY
: to remove moisture from (as air)

While they reduce relative humidity by changing the temperature, they do not remove any water. They should call them what they are.

You can by an actual small dehumidifier for less.

 

We are actually in the Galveston area. It's humid, but not as much as PNW, at least I think. I'm really not sure of that. It's just very hot in the summer in the Houston areas, with the humidity, feels like you're in a sauna. I believe we'll be leaving our hatches and windows open at night, except for in bad weather. We do have an AC/heater, so maybe that will help. But as you say, with two of us sleeping and living on board all the time, we may have to turn it on during the colder weather when we can't open the ports and hatches.