Mungo and the Tropical Rainforest

or:  the Condensation follies.

I was in one of the big box hardware stores the other day, and I saw a couple wrangling over what humidifier to buy.  I found myself wanting to go grab them and say "Are you out of your minds?  That thing puts water IN the air!!!"

Okay, so we've lived on a boat for a bit.  It's kind of odd, when normal homeowners are looking to put water INTO the air, we're looking to take it out.

In winter, the air outside is bone dry.  Inside, not so much.

For those of you ignorant of the joys of living aboard (and I kid, there are many), if it's a modern vessel you are living in an impermeable shell of fiberglass.  The purpose is, of course, to keep water out, which it does admirably. One of the side-effects, though, is that it also keeps moisture in the boat.  You exhale, the moisture goes into the air.  You make dinner and reduce an inch of soup stock, that inch of moisture goes into the air.  You turn on a Propane heater, it pumps moisture into the air as well.  You use the composting toilet, some of the moisture goes into the air.  No big deal, of course.

Until it's winter and the outside air chills the hull and the deck house.  Then the moisture condenses. .

. . .in the main berth. . .

. . .right over your heads.  The long and the short of it is, it can literally rain inside.  It can do it on some of the coldest, most unpleasant days of the year, and it can make your bedding and clothes sodden even though you have refrained from using the squirt guns in the boat all year like your wife told you she'd leave you if you didn't do....

Nuff said

Over our five years aboard, we've tried a number of solutions with varying success, so I thought I would detail a few of them to help get you guys into spring without your bedding rotting or you contracting pnumonia.

First and foremost--and this is a simple one--occasionally vent the boat.  Just open everything up, even if it's cold outside.  You shouldn't leave it open long enough for surfaces to cool off (which you would then have to heat back up again) but enough to flush out the warm, wet air with dry, cooler air from outside.  Doing this periodically really helps, but obviously you can't do it too often or you'll wind up with a heating bill approaching the national debt.

Adding more insulation helps quite a bit as well, preventing  the creation of cold surfaces on which water may condense and has the side advantage of making your vessel warmer and lots more cosy.  This doesn't, however, remove any water from the air, and in a lot of vessels there just isn't the room to add a lot of new insulation.  Things like ecofoil (metalized bubblewrap) are a decent option for oddly shaped, hard to get at spaces.

Small solid fuel stoves can really help dry out the air, but their mere presence alarms a lot of Marina owners.

Solid fuel stoves--Charcoal, wood, wood pellets and the like--are great at drying out the air.  They pump a lot of damp interior air up their chimneys and draw in dryer outside air to replace it, and that works.  The times we've used a wood burner aboard the air has been pretty much bone dry.  The problem is: a lot of Marinas and insurance providers are terrified of wood burners, fearing the sparks (frankly, I think propane is far more dangerous) and won't allow them.

Small USB fans are great for drying surfaces prone to condensation.  Plus they help when it's hot too.

Next up--and this one surprised us--fans.  This last winter we tried pointing a few low wattage usb fans at the places that were condensing the worst and, lo and behold, they dried off.  For such a low cost, low power alternative, they have been amazingly effective.  Presumably the water condenses elsewhere, like in the hull, but at least it's not over the bed.

Lofting your bedding so some air can get underneath the mattress can really help keeping the bottom of your cushions from getting drenched.  It doesn't have to be much, just a few millimeters, just enough so any water under there can evaporate and escape.  The water is coming from you, and it can eventually utterly saturate your mattress.  Caveat.

Chemical dehumidifiers like DampRid do work and pull a surprising amount of water out of the air, but they're disposable, fill up quickly, and are expensive over time (and often rather messy to deal with).  Not our fave.

Small, compressor-less Peltier device dehumidifiers are a low power option for small spaces.

They don't however, remove a huge amount of moisture.  Here's the removable water tank.  Not large.

We have also used a couple of small, Peltier device dehumidifiers currently on the market.  The things are very small,  have no compressor, and consume very little juice, but they only can remove a very small amount of water from the air.  They're ideal for small, enclosed spaces like lockers, but not really terribly well suited for larger, wetter spaces.

In the past, true compressor based dehumidifiers were kind of out of the running for a lot of vessels.  They were too big and ate too much power (a 40 pint dehumidifier is almost the size of a small refrigerator and uses a lot more juice.)  Lately, though, we've seen a number of 20 pint or less units hit the market.  These gizmos are very quiet, small enough to sit on a counter, and can pull the same amount of water out of the air in a couple of hours as one of the Peltier device units can do in a month.  They do, however, consume a fair amount of electricity.

New, 20 pint and less compressor dehumidifiers can sit on a counter.

In a few months, the weather will turn, the air will warm, and condensation won't be an issue.  We'll forget all about it until the first frost of next fall, when our own little rain forest will trigger a mad scramble to dig up one of the above solutions.  Living aboard a boat, you live with nature, good and bad, and have to adapt as best you can.  It's a small price to pay to wake up on the water.  Wouldn't have it any other way.

More shortly.  Enjoy the coming spring.

M