Cabin Moisture / Dehumidifier

Posted by Rick Higgens (higgens@…>)

Hello all, I am wondering if anyone has gone the route of using a
small dehumidifier in their cabin to remove moisture vs. a fresh air
intake / exhaust vent solution? I just hate making extra holes in my
boat! They have some pretty small units now, about the size of a
small space heater, and with some modification (drill a hole in the
bottom through the collection reservoir) it could be placed on the
sole in the head and drain into the shower sump. My only fear is if
this would do to good of a job dehumidifying and maybe dry out the
wood. Any experience?
Rick F30 Nauti-Belle

Posted by Herman and Gail Schiller (hschiller2@…>)

I’ve installed a 3" Nicro day-night powered ventilator in the head’s
hatch in my Mull 28. I also put a 4" version of this in the fore deck
hatch over the V-berth. These things will run all night, albeit at
reduced speed compared to when sunlight is hitting their solar
panels. These seem to keep the boat from developing any mildew. These
actions are reversible; one can replace the glazing in the hatch to
remove the vents.
If there are really small dehumidifier units, that won’t eat a lot of
kilowatt hours, I would assume that there is a control on them using
a humidistat to let you set the level of humidity you desire. The
larger ones I’ve owned have such controls, but eat kilowatts like a
window air conditioner.

BTW, I live in the humidity capital of the U.S., Eastern, NC.

Herm

At 03:23 PM 10/22/2007, you wrote:

Hello all, I am wondering if anyone has gone the route of using a
small dehumidifier in their cabin to remove moisture vs. a fresh air
intake / exhaust vent solution? I just hate making extra holes in my
boat! They have some pretty small units now, about the size of a
small space heater, and with some modification (drill a hole in the
bottom through the collection reservoir) it could be placed on the
sole in the head and drain into the shower sump. My only fear is if
this would do to good of a job dehumidifying and maybe dry out the
wood. Any experience?
Rick F30 Nauti-Belle

Posted by Rick Higgens (higgens@…>)

Thanks for the reply Herm, we are also in NC, Oriental to be exact so
humidity is a concern. I bought the square Nicro day/night vent to
put in the head but on the F30 some of the lines coming down the port
side cross right over the head hatch and it seemed like a repair
waiting to happen. Also did you do anything for fresh air intake or
do you run one vent intake and the other exhaust? Seems like in order
to be effective it has to be able to pull in fresh air from somewhere.
I thought about making up some sort of removable port “shade” that
I can attach on the port that opens into the cockpit. By the way,
these little dehumidifiers don’t have the controls a full sized unit does.
http://cgi.ebay.com/Small-Portable-Compact-Mini-Dehumidifier-
Air-Dryer-NEW_W0QQitemZ190164147723QQihZ009QQcategoryZ79621QQss
PageNameZWDVWQQrdZ1QQcmdZViewItem

http://cgi.ebay.com/Brand-New-Portable-Compact-Dehumidifier-Air-Dryer-
Quite_W0QQitemZ170159990292QQihZ007QQcategoryZ79621QQssPageName
ZWDVWQQrdZ1QQcmdZViewItem

— In FreedomOwnersGroup@yahoogroups.com, Herman and Gail Schiller
<hschiller2@…> wrote:

I’ve installed a 3" Nicro day-night powered ventilator in the head’s
hatch in my Mull 28. I also put a 4" version of this in the fore deck
hatch over the V-berth. These things will run all night, albeit at
reduced speed compared to when sunlight is hitting their solar
panels. These seem to keep the boat from developing any mildew. These
actions are reversible; one can replace the glazing in the hatch to
remove the vents.
If there are really small dehumidifier units, that won’t eat a lot of
kilowatt hours, I would assume that there is a control on them using
a humidistat to let you set the level of humidity you desire. The
larger ones I’ve owned have such controls, but eat kilowatts like a
window air conditioner.

BTW, I live in the humidity capital of the U.S., Eastern, NC.

                                     Herm

At 03:23 PM 10/22/2007, you wrote:

Hello all, I am wondering if anyone has gone the route of using a
small dehumidifier in their cabin to remove moisture vs. a fresh air
intake / exhaust vent solution? I just hate making extra holes in my
boat! They have some pretty small units now, about the size of a
small space heater, and with some modification (drill a hole in the
bottom through the collection reservoir) it could be placed on the
sole in the head and drain into the shower sump. My only fear is if
this would do to good of a job dehumidifying and maybe dry out the
wood. Any experience?
Rick F30 Nauti-Belle

Posted by katorpus (jrb@…>)

I use the “full-size” one in my Freedom 40 (more cabin space).

If you get one with the humidistat, it won’t run any more than
it “has to” to maintain the humidity level which you set.

Here’s how I use mine…

I placed it on the galley countertop beside the galley sink, with a
short piece of garden hose leading directly to the sink strainer
(which doesn’t have to be in place). The hose connects to a fitting
which was molded into the “bucket” for the dehumidifier just for that
purpose.

After going through several of the cheapie “dial type” on-off timer
switches, I bought one of those ($50 or so) gray metal box wire-in
timer switches like the kind that you use for outdoor light circuits.
You have to wire up the pigtail to plug it into the wall, but that’s
easily done.

I set the humidistat for about 60% relative humidity, and set the
timer to run for 12 hrs a day beginning at dawn. My interior stays
dry enough that the floorboards creak. There is no such thing as “too
dry” where the interior wood is concerned.

I also use a Quantum ozone generator plugged into to the power strip
that’s wired into the timer box.

I keep the boat closed up tight with no outside air circulation. I
never have any mildew, “boat smells”, nor stink of diesel down below.

Several things to consider…In cooler weather, a more-or-less
continually running humidifier will freeze up (on the coils of the
unit). Hence the timer and the timing (daytime running, when it’s
warmer).

These things do put off some heat. Expect it to warm up the interior
of the boat quite a bit when it’s running.

If you drain a dehumidifier into your shower sump, you’ll
be “exercising” the pump (associated with the sump) quite a bit. If
you can place the unit where “gravity” does the work (like over a
sink) then, assuming you don’t close the through hull for the sink
when you’re away from the boat (I only do this when a serious storm
is approaching), then it won’t “cost” you anything to get rid of the
water that’s extracted from the air.

The sump pump won’t wear out, and you won’t be re-extracting the
water from the air that results from it trickling into the shower
drain and/or sitting in the sump awaiting a pump cycle. If it takes a
pint of water to “trigger” your shower sump, and your dehumidifier
removes 20 pints a day, then assume that you’ll have at LEAST 20
cycles per day of your sump pump (more actually, as the motion of the
boat in the slip will likely trigger it more often due to sloshing).

A less-capable (hence less-efficient) dehumidifier operating more
hours per day will not save you kilowatt hours.

The bigger ones ARE more of a pain to move around when you get ready
to go sailing, but they’ll fit in a dock box.

Posted by Herman and Gail Schiller (hschiller2@…>)

Rick,
I live on a small peninsula in Fairfield Harbour with warm
shallow water on three sides. Both my Nicro vents are exhausting. I
have some stainless steel louvers on the upper companionway board
(Acrylic panel), and the gap at the top of the companionway
supplements that air flow. Perhaps a bit more air comes from the
cockpit hatch via the little hatch for garbage disposal in the galley
and through the rope deck pipe in the bow. On my Mull F28, the triple
deck organizer is at the forward port corner of the head hatch, and
leads the lines around rather than over the hatch. I find your
line-routing problem odd because the F28 and F30 seem to be very similar.
Herm

At 05:26 PM 10/22/2007, you wrote:

Thanks for the reply Herm, we are also in NC, Oriental to be exact so
humidity is a concern. I bought the square Nicro day/night vent to
put in the head but on the F30 some of the lines coming down the port
side cross right over the head hatch and it seemed like a repair
waiting to happen. Also did you do anything for fresh air intake or
do you run one vent intake and the other exhaust? Seems like in order
to be effective it has to be able to pull in fresh air from somewhere.
I thought about making up some sort of removable port “shade” that
I can attach on the port that opens into the cockpit. By the way,
these little dehumidifiers don’t have the controls a full sized unit does.
<http://cgi.ebay.com/Small-Portable-Compact-Mini-Dehumidifier->http://cgi.ebay.
com/Small-Portable-Compact-Mini-Dehumidifier-
Air-Dryer-NEW_W0QQitemZ190164147723QQihZ009QQcategoryZ79621QQss
PageNameZWDVWQQrdZ1QQcmdZViewItem

<http://cgi.ebay.com/Brand-New-Portable-Compact-Dehumidifier-Air-Dryer->http://
cgi.ebay.com/Brand-New-Portable-Compact-Dehumidifier-Air-Dryer-
Quite_W0QQitemZ170159990292QQihZ007QQcategoryZ79621QQssPageName
ZWDVWQQrdZ1QQcmdZViewItem

— In
mailto:FreedomOwnersGroup%40yahoogroups.comFreedomOwnersGroup@yahoogroups.com
,
Herman and Gail Schiller
<hschiller2@…> wrote:

I’ve installed a 3" Nicro day-night powered ventilator in the head’s
hatch in my Mull 28. I also put a 4" version of this in the fore deck
hatch over the V-berth. These things will run all night, albeit at
reduced speed compared to when sunlight is hitting their solar
panels. These seem to keep the boat from developing any mildew. These
actions are reversible; one can replace the glazing in the hatch to
remove the vents.
If there are really small dehumidifier units, that won’t eat a lot of
kilowatt hours, I would assume that there is a control on them using
a humidistat to let you set the level of humidity you desire. The
larger ones I’ve owned have such controls, but eat kilowatts like a
window air conditioner.

BTW, I live in the humidity capital of the U.S., Eastern, NC.

Herm

At 03:23 PM 10/22/2007, you wrote:

Hello all, I am wondering if anyone has gone the route of using a
small dehumidifier in their cabin to remove moisture vs. a fresh air
intake / exhaust vent solution? I just hate making extra holes in my
boat! They have some pretty small units now, about the size of a
small space heater, and with some modification (drill a hole in the
bottom through the collection reservoir) it could be placed on the
sole in the head and drain into the shower sump. My only fear is if
this would do to good of a job dehumidifying and maybe dry out the
wood. Any experience?
Rick F30 Nauti-Belle