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Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Learn from my air conditioner mistake!

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soulfinger
1st Mate

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USA
29 Posts

Initially Posted - 07/26/2007 : 19:38:22

In order to make sleeping aboard tolerable here in houston, A/C is a must. Instead of going with the classic companionway-mounted window unit, I decided to go all fancy and get one of those new-fangled "Portable" A/C units that look like R2D2 with a big hose coming out the back. That way, we can have A/C without putting a major obstacle getting in/out of the cabin.

Big mistake.

There's a catch to these things---sure, they make tons of cold air by sucking the heat out of it. However, due to the unfortunate laws of thermodynamics, all that heat has to go somewhere. Now, on a normal home A/C unit, the heat is deposited outside, the cool air inside is recirculated and cooled. The problam with the new portable type A/C's is that they have to do something with all that heat, since there's not a direct heatsink to the outide. So what they do is put in another big fan that blows all the heat out through a hose, which you run to a window, hatch, etc. This all works fine in theory, but there's a catch! You're using a fan in the unit to pump all this now-hot air outside, but you're also creating a tremendous negative pressure within the cabin (or your room if used in a house), which then starts sucking in all the hot air that's outside. I'm sure there's some net cooling effect, but it's really not nearly as effecient as a more conventional A/C unit. We had an 8000 btu unit, and our C250 was still quite uncomfortable, even with it running constantly. It gets even worse, because while most A/C's will also dry out the air, this one keeps on sucking in more humid air from the outside (think steamy marina in texas during july), which is progressively deposited in the cabin. A total disaster.

Thankfully, after much pleading, the people at Home Depot that we bought it from allowed us to return it. We've learned our lesson, and I'm off to get a small window unit for the companionway, which I might add costs 1/3 of what the failed portable unit cost.

If you don't know what I'm talking about:

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100522321&N=+503405+4294963597+90401

Edited by - on

Tom Potter
Master Marine Consultant

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USA
1913 Posts

Response Posted - 07/26/2007 : 19:56:01

Thanks for posting this Andy. I WAS seriously thinking of getting one of those.

Edited by - on

DaveR
Master Marine Consultant

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USA
2015 Posts

Response Posted - 07/26/2007 : 20:35:36

It had crossed my mind as well, thanks for the heads up!

Edited by - on

iain
1st Mate

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Canada
25 Posts

Response Posted - 07/26/2007 : 20:37:05

soulfinger, try here.

http://www.sailboatowners.com/upload/display.tpl?folder=73176767101&fno=79

also, on page 42 (i think) of this forum look for 'portable
air conditioner' by cat1951.

a long disc. about your topic.

i everyone, had to join so that i could pass the above along.

moderator/web guy. on reg. i was told to put my age in as a req.
firld. that field is not marked as req.

also, i lied about my age....a bit

iain, like ian.

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 07/26/2007 : 20:59:37

Welcome, the age thing is to stop bots, fudge all you want.

Edited by - on

Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 07/26/2007 : 21:12:53

I was thinking about one of those units for my attic - 12000 BTU with heat/cool/dehumidifier for a room about 350 square feet. If the room is well insulated will it be drawing the cooler air from the lower floors to fill the negative pressure void?

As noted, Most of the bot programmers know the code for this free forum ware so they can keep loading up the forum with new users and then post a zillion erectile dysfunction drugs, (So many wisecracks I can go with here - but I'll be nice to you old timers)

Anyway the age throws the program off and the code errors out and they move on.

I believe one of the ages on one of the accounts says I am negative 1

Edited by - on

soulfinger
1st Mate

Members Avatar

USA
29 Posts

Response Posted - 07/26/2007 : 21:27:10

It's going suck air from whereve it can get it easiest! I can't think of any particularly good use for one of these things, except maybe if you lived in a condo or apartment with air conditioned hallways---you could crack your door and use it to suck in the cool air from the hallway!

There was a good article in "Good Old Boat" recently about how to hatch-mount a window unit. I've thought about it, but I just don't see it working well in our C250 for two reasons:

1) It's a fairly tippy boat, and it would really have to be lashed down to the deck well to prevent it from sliding off into the drink.

2) It would work better if the hatch were in the middle of the cabin--as is, all the cool air would blast onto our faces in the V-birth, and might not circulate as well to the rest of the boat.

Sure, mounting in the companionway has its drawbacks, but I think it's the best route, short of cutting a big hole in the side of the hull and hanging it out there!

Edited by - on

iain
1st Mate

Members Avatar

Canada
25 Posts

Response Posted - 07/27/2007 : 07:09:42

hi again. sorry about all the sp's mistakes in my last post.
i have now learnt not to type in the dark.

home depot sells those a/c's and i almost bought one.
but when i saw the price i balked. they also have buyer reviews
about the mach's. with the at-the-time 50% neg. (2 out of 4)
reviews and the cost, i went with a loews 5000 for $100.

if i set that link(above) correctly you folks should get a better
idea for your a/c.
on another related note:
i would hate to block my access to the companion way for emergency
reasons i.e.; FIRE!

yes, i know, you can always use the forward hatch. i also know
that most of you have youngish kids or gr'kids. would you
trust theirs and your safety to an 18" sq hole??

iain
transient in being.
s. am.se asia.eng. can. us.
lake perry, ks.
and no i will not get involved with the gun issue.

Edited by - on

iain
1st Mate

Members Avatar

Canada
25 Posts

Response Posted - 07/27/2007 : 07:18:22

try this again!

has anyone looked into a/c's for r/v's
and then checked their a/b/c's?

i know they are expensive, but they are also compact
and run in a similar environment as sailing.

iain

Edited by - on

britinusa
Web Editor

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USA
5404 Posts

Response Posted - 07/27/2007 : 07:48:16

How about this...

Paul.

Edited by - on

ilnadi
Captain

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452 Posts

Response Posted - 07/27/2007 : 08:13:31

I looked at those, attractive in not blocking the companionway BUT:
<ul><li>expensive compared to same BTU window unit</li><li>have to get a "two-hose" model, which will more upper end (see towards the top of the page http://www.portablecoolers.com/air-conditioners/air-conditioning.html#LX-120)</li></ul>

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by soulfinger
So what they do is put in another big fan that blows all the heat out through a hose, which you run to a window, hatch, etc. This all works fine in theory, but there's a catch!
<hr height="1" noshade id="quote"></blockquote id="quote">

Edited by - on

Oscar
Master Marine Consultant

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USA
2030 Posts

Response Posted - 07/27/2007 : 08:51:27

I built a marine water cooled unit into a 250WB.....not cheap, $1600 or so in the end, but VERY effective and completely out of the way....(behind the aft bulkhead.) Dig deep on this forum under my name and you'll find it, complete with pics.

There is of course the cruisair-portable solution that sits on the forward hatch.....you can get one of those well under $1000.

I would NOT put an RV ac on a boat.

Edited by - on

lewalskim
1st Mate

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USA
70 Posts

Response Posted - 07/27/2007 : 09:34:38

I have pictures of a small A/C unit ($80 or so from Wal-Mart) that was mounted in the hatch of a C250. I believe that the photo came from and the mod was done by Mark Melchior but I can't find it on his website [url="http://www.texassailor.com/"]http://www.texassailor.com/[/url] anymore. If I remember correctly, he said that he had to step over it to get in the cabin but that it wasn't too bad. He also said that it kept it FROSTY inside.

I'm sure that other members have similar installation but soulfinger, you might try emailing Mark Melchior about it.

Edited by - on

Tom Potter
Master Marine Consultant

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USA
1913 Posts

Response Posted - 07/27/2007 : 14:35:00

Paul,
That picture looks somewhat familiar to me. I just can't place it...

Edited by - Tom Potter on 07/27/2007 14:35:31

britinusa
Web Editor

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USA
5404 Posts

Response Posted - 07/27/2007 : 17:42:56

I'm with Oscar, the built in coolair system from West Marine - the only reason you would know it was installed would be due to the bulkhead I installed on the port side of the companionway steps. And FROSTY Oh Yeah! we turn it down to about 50% at night and keep a blanky handy. Doesn't use any real space in the aft berth either.

The only issue we have had with our install is the need to prime the pump. I also have a power water pump, so I just lean over with the nozzle and squirt water into the outflow for about a minute, then flash up the chill machine, close the boat up and cooooooool!

We also purchased the 2 year warranty, just in case it has any issues before June next year (marked on our calendar!)

Oscar, did you install yours in the trunk?

Paul

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 07/27/2007 : 17:51:08

Paul, did you use 5200 or silcon caulk to seal that AC against the hull?

Edited by - on

Oscar
Master Marine Consultant

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USA
2030 Posts

Response Posted - 07/27/2007 : 18:58:00

Here's the $100 solution...

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Oscar, did you install yours in the trunk?<hr height="1" noshade id="quote"></blockquote id="quote">

Behind aft bulkhead.....yes, I now remember having to prime the pump.....lol.

Ducting from unit....with "T" over aft bunk and outlet next to companion way...

The pump in the "bilge" of the Watrer Ballast......a wing should be easier.

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 07/27/2007 : 19:04:30

Tough to have a pump beneath the waterline on a WB, huh?

Edited by - on

britinusa
Web Editor

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USA
5404 Posts

Response Posted - 07/27/2007 : 20:25:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Tough to have a pump beneath the waterline on a WB, huh?<hr height="1" noshade id="quote"></blockquote id="quote">

Yep, it's pretty skinny in there. But I must admit, Oscar did a really nice job of fiberglassing in his breadboard there. Very neat job. I mounted our pump on a starboard with diagonally cut sides that slips into a pair of matching holddowns. So I can just remove the retainer and pull the whole pump assembly out. Note how Oscar correctly placed steel strap clamps around the tubing with the bolts facing opposite directions to prevent loss of both if vibrations shake one loose.

Paul

Edited by - on

britinusa
Web Editor

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USA
5404 Posts

Response Posted - 07/29/2007 : 11:29:25

Just found this on [url="http://cgi.ebay.com/ebaymotors/new-sailboat-sail-boat-rv-stainless-air-conditioner-a-c_W0QQcmdZViewItemQQcategoryZ26451QQihZ017QQitemZ270148173959QQrdZ1QQsspagenameZWDVWQQtcZphoto#ebayphotohosting"]ebay[/url]

Paul

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 07/29/2007 : 11:36:14

It is huge!

Edited by - on

iain
1st Mate

Members Avatar

Canada
25 Posts

Response Posted - 08/05/2007 : 15:06:55

o.k., try this again...forgot to sign in

"I would NOT put an RV ac on a boat."

oscar, why 'knot'?

britinusa - i like your idea, but think it should be more
amidship for even dist. of air.
also like your handle.

maybe i can call myself
canuknusa or britcanuknusa or trinidadianbritcanuknusa.
nah, transient sounds better and is shorter.

Edited by - iain on 08/05/2007 15:17:54

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