Mini Dehumidifer

seadaddler · Mar 31, 2012

Ditto

5 years ago up in NY I had one like it and did same thing as drilled hole so it would drain in sink and it died after 2 years but with my new 2007 H-36 it has AC and the AC has a Humid stat setup that goes on every 3 to 4 hours to remove moisture,if I did not have system I would most likely get one of the small unit you got.
Nick

kloudie1 · Mar 31, 2012

Just did some thumbnail numbers and my guesstimate is that you'll need a capacity of about 10 pints a day on a 30 foot boat to do useful dehumidification. If you seal the boat that would drop a good bit but my gut feel is that the little unit is too small except for a confined space. I used to run a 35 pint a day unit on my 34 and it was plenty big enough..Now I have a dehumidify cycle on the AC like Nick uses.. That works very well.

Sailm8 · Mar 31, 2012

Yes the pump runs

Benny17441 · Mar 31, 2012

A friend gave me one after he got frustrated with it. I used it for a few days and it really does not dry, it does remove water but I think the humidity just slips through the cracks as fast as it is removed. Perhaps if you seal the boat like Kloudie suggests. We keep a compressor driven dehumidifier at 50% setting and you feel the dry light heat air as soon as the boat is opened. We have the discharge hose going in to the bilge.

Stu Jackson · Mar 31, 2012

Benny17441 said:
Perhaps if you seal the boat like Kloudie suggests.

My understanding is that sealing a boat is the worst thing you can do. Nicro recommends "ventilation, ventilation, ventilation" like the real estate "location..." stuff.

Perhaps it's different where it's very humid and/or hot all the time.

While I agree that an AC unit with a dehumidifier setting is the right way to go (we had a powerboat on our dock a few years ago and I thought it was his bilge pump operating so frequently, but he told me about his AC unit), I'd think a sealed ship would be the worst thing you could do to attract mold and mildew.

Do they make Driz-e-Air anymore? I used that on our C22 years ago. Crystals in a container with a big cup below dropped a lot of water over the course of a week or two. No power required.

Ross · Mar 31, 2012

Calcium chloride is very hydroscopic and is the active mechanizm in most of these "air driers". But you need a very large surface area to have them be very effective.
Ventilation has worked perfectly well on Bietzpadlin for twelve years.

jimmcgee · Mar 31, 2012

Billy, I'm wondering why you feel you need a dehumidifier?

We're close by (Barnegat Bay). I have a Nicro solar vent in the v-berth. It probably runs 20 hours a day and keeps air moving in the boat. In August we flip on the AC when we get to the boat and she's cooled down in 20-30 minutes. Even before we had the AC we never had a mildew problem.

As for leaving the AC running in de-humidfy mode, it makes me nervous. I know the big powerboats in our marina all do it, but what if I suck up something that kills water flow? At best I'll kill the pump from running it dry.

John Nantz · Mar 31, 2012

Must be below 50% RH to stop mold and mildew

Just having a dehumidifier isn't necessarily going to stop mold and mildew. The unit must be capable of getting below 50% RH to do the job.

For a compresser-type dehumidifier, to get below 50% RH it will need defrost capability.

We've had one on our boat for several years now and what is nice is when you open the hatch and go down below it smells nice and fresh. No odors.

The operating cost where we are is much less, like about 1/3, of the round heater-types with the holes in the top. Because the unit operates with a humidistat it turns itself off when the humidity reaches the set point which I usually have at 45% RH. If we have had a power outage I'll drop that down to 40% RH for a while.

kloudie1 · Mar 31, 2012

Sealing the boat AND removing the moisture from the air will keep the mold/mildew at bay.. You are correct, Stu if ya seal it and do not take the moisture out, the normal hot/cool cycles will condense some water and start the mold farm.. Dessicant dryers like calcium chloride work, but here the life is so short that it is not worth fiddling with. You'd have to change out the calcium compound every coupla days to keep it working. My dehumidifier would pull bout a gallon-and-a-half out a day.. That is with the dorades and hatches closed. but a couple of VETUS passive vents open which pull air through the boat from companionway and cockpit locker imperfect seals.
Yes the pump runs and ya have to keep an eye on it because it can sink the boat quickly. The computer control for the pump protects the system in the event the water flow gets restricted. It is just like losing the condenser fan in a home unit.. it will trip out on high discharge pressure.

Benny17441 · Mar 31, 2012

Well talking about sealing the boat is just an exageration to try an illustrate how inadequate the peltier effect dehumidifier is. My dehumidifier has a 50% setting, do not know how that relates to the percentage of humidity in the air but having lived in the Southwest I know what dry air feels like and the cabin feels pretty dry to me. Here in the Gulf Coast of Florida our humidity in the summer months hovers around 97%+. I have had my A/C unit cooling water intake port bocked by a discarded ice plastic bag and guess what, the compressor shut itself off until the blockage was removed and it was restarted. I'm into things that work and if something does not work I discard it. A compressor driven dehumidifier does work and it keeps the boat smelling good; no musty odors.

dparilla · Mar 31, 2012

Winter is usually dry enough that a dehumidifier is unnecessary. Average humidity even in the swamp of DC stays below 50% for the winter. I have used the AC to help maintain temps and humidity in the peak of summer, yes it requires living a valve to sea open, but I have a high bilge alarm connected to the SPOT HUG so if it were to have a leak, I would be notified.

gpd955 · Apr 1, 2012

Billy, you may be on the right track in trying to get your bilge dry. My C30 had several small leaks and there was always some water in the bilge and I was constantly wiping the cabin down to remove areas of mildew. My 310, which doesn't have a single area of ingress (tumbleweeds come out of my bigle when I open it and I actually saw a cow skull one day

) has never had a spot of mildew in it. I actually go on mildew hunts and haven't been able to find any.

Are you sure that there are no areas other than the bilge (like in the storage areas behind the salon and lazarette cushions) where water is standing?? Are those areas of mildew in isolated locations or random areas?? I'm going to be on my boat next weekend (and will be in OC to get our 1/2 price tix for our son!) and if you need a hand looking for issues, I'd be happy to stop by.

Lost Parent · Apr 1, 2012

On a Catalina 30 1982 were would you drain the humidifier without leaving the sink through hull open...bad idea

Steve Dion · Apr 1, 2012

Lost Parent said:
On a Catalina 30 1982 were would you drain the humidifier without leaving the sink through hull open...bad idea

Second option - Bilge or shower bilge

Mini Dehumidifer

BillyK

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seadaddler

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kloudie1

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BillyK

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Sailm8

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Benny17441

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Stu Jackson

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Ross

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jimmcgee

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John Nantz

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kloudie1

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Benny17441

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BillyK

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dparilla

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gpd955

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Lost Parent

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Steve Dion

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BillyK

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BillyK

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