Installed a portable AC/Dehumidifier on my 330

[Flot]

Down here in S Florida it is hot and humid 10 months out of the year, and raining every other day on top of that. My neighbor has a 26' walkaround and every time he opens it up he's greeted with mildew, mold, etc on every surface. Not what I wanted to deal with on my first boat with a cabin.

So when I brought the Grady home, I bought a large portable dehumidifier for the boat, which worked great, BUT it made the cabin awfully hot. That isn't the end of the world when it was 75 degrees out, when it was 85 degrees outside it got ridiculous.

I keep the boat on a lift, so running the cabin AC unit wasn't an option, plus I didn't like the idea of leaving those seacocks open all the time and running those components 24/7.

So to tackle all of this, I installed a portable AC unit - my only regret is that I got a "single hose" model, mostly because a 6500-8000 btu dual hose unit seems to be impossible to find. To mount it, I traced out the aft hatch panel onto a sheet of 3/4" plywood, cut out the shape of the unit, and then built a shelf for it to rest on 3" underneath. The result is that the AC unit is pretty much locked into place on the plywood, the drain assembly is below the cabin floor and drains through a hose into the bilge, and after a lot of debate with myself, I vented the air exhaust hose out the rear cabin window so that none of this is permanent. (I still may go back and vent it through the starboard side tackle locker)

In theory, I could supplement or replace the bulit in cabin air, but that's not really my goal, my goal was just to knock down humidity when I'm not using the boat - let's be honest, I'm using the boat 5-6 days a month and it's sitting there the other 25.

So far so good! I have plans to replace the rear cabin carpet with EVA form flooring anyway, so I'll just cut out around the hatches and line up both the original hatch and the A/C hatch with the pattern. My only real mistake was that I mounted it a little too far forward, I should have pushed back a bit further but the output hose does cause some clearance problems. For me the aft cabin is mostly storage, and if I want to undo this for a trip where I need the aft bunk, I can just lift it out.

I was surprised to find there were really no good solutions for dehumidifiers for stored boats. My options were either $39 units that would remove a couple of pints a day or $200 units that were overkill. This is certainly overkill but has the added benefit of cooling the cabin.

 

[wspitler]

My 330 is also on a lift in FL. I use a larger dehumidifier and you are right it does make it awfully hot in the cabin. I see you drain the condensate into the bilge. It seems that just moves the water from one place to another and there is a lot over time. If I copy your idea I'll try to drain the water into the shower sump and let it be pumped overboard. Might take a little tubing and a hole saw, but it would keep the bilge dry and reduce the mold down there. I'll need to leave a battery on and just the sump switch on the DC side, but I have on board 4 bank charger so it should work. Do you leave the enclosure on and let AC get to the helm area as well? To do that would require modification of the aft enclosure door to allow exhaust. Also what model HiSense AC did you install, you source and cost? Thanks for the idea!

 

[Flot]

wspitler, I have a pretty wet bilge at the moment so figured one more drip wouldn't matter. The way it worked out, the hose creates it's own "p-trap" before connecting to the bilge which also made me feel better about making that connection. My dehumidifier was the same general size/shape as this AC unit, and I kept it in the dip in the floor, it actually fit well there, but the exhaust hose coming off the AC unit made that a bit ridiculous.

The shower sump is a good idea although I wouldn't want to leave my entire 12v system energized - easier to run that one pump with float directly to a battery the same way you'd hook up a backup bilge pump. Lots of ways to work that out. Originally I had visions of a compact dehumidifer draining into the galley sink, but I couldn't find one small enough to put on the counter that was also big enough to put a dent in the humidity.

I think adding the enclosure to the mix would be a bit too much for this to handle, I leave that open to breathe. My original plan was to cut a 5" hole in the back of the knife/tackle storage and pipe into there - then I would just leave that box open when the boat is on the lift, but the rear porthole was just too convenient.

The Hisense AC is a regular stocking model at lowes, the smallest "portable" AC (8000 btu) they sold and it was about $300. Dimensions are approx 12x13x30. I'll report back in a week or two on how it does overall. I had most of the aft cabin berth out for the last week as I was doing some other work, so the whole cabin was a little funky, got it all reassembled this afternoon so the mechanical areas and living areas are separated again.

The problem with the single hose AC is that it pulls a ton of air INTO the cabin to exhaust the hot condenser output. So the AC is constantly working against itself. I struggled with this but eventually decided it was the best I could do, hopefully most of that fresh air comes in through the cabin door vs sneaking through other cracks and crevices. Still, the worst case is that it is pulling fresh air through the cabin.

Baffles me that nobody makes a simple, compact marine dehumidifier. I even considered some basement crawlspace units, but almost all of them get pretty hot. I did find one somewhere that had a slight net cooling effect but I think it was pushing $1500+. I would have thought there was a real market for some sort of compact unit with a drain hose but there's not a lot out there.

 

[Flot]

Jury is still out on this modification.

When I had the large portable dehumidifier in the boat, the cabin was getting scorching hot, but it was keeping a lid on the humidity. I could keep it at 65-70%.

With the stupid single-hose portable AC unit, whenever the unit is running it will drag the humidity quickly down to 50% or so. However, as soon as it starts its compressor cool down cycle, the humidity jumps up as it draws in fresh air, and overnight it doesn't run at all - so the humidity will reach 80%+ until the AC happens to kick back in.

I also discovered by relocating the unit back to the aft berth, while the positioning is fantastic for keeping it out of the way, the airflow patterns are weird because of it. A small fan (which seems absurd) is helping this a lot and may be helping the overnight humidity as well. We'll see.

If they made a 6500-8000 btu "dual hose" AC, that would be the ticket. But the dual hose units are monsterous in size.

 

[Xikky]

Jury is still out on this modification.

When I had the large portable dehumidifier in the boat, the cabin was getting scorching hot, but it was keeping a lid on the humidity. I could keep it at 65-70%.

With the stupid single-hose portable AC unit, whenever the unit is running it will drag the humidity quickly down to 50% or so. However, as soon as it starts its compressor cool down cycle, the humidity jumps up as it draws in fresh air, and overnight it doesn't run at all - so the humidity will reach 80%+ until the AC happens to kick back in.

I also discovered by relocating the unit back to the aft berth, while the positioning is fantastic for keeping it out of the way, the airflow patterns are weird because of it. A small fan (which seems absurd) is helping this a lot and may be helping the overnight humidity as well. We'll see.

If they made a 6500-8000 btu "dual hose" AC, that would be the ticket. But the dual hose units are monsterous in size.

Could you Jerry rig a setup to make the small ac into a dual hose? Might be able to take off the front cover and make something

 

[gman3586]

Just curious if you have any update on how things are going with the portable AC unit. I was thinking about doing something similar on my 330 that is on a lift. Is it keeping the humidity at an acceptable level? Also, will that unit cool the cabin down in the evenings in FL? Thinking about sticking my brother's son and his friend out there to sleep when they visit.