I'm an A/C convert

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DaveC426913
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I'm an A/C convert

Post by DaveC426913 » Mon Jul 02, 2018 4:12 pm

Some time ago, I was astonished at the idea of installing an A/C unit in the hatch of a Mac.

Today, I am no longer astonished. Temperatures over the long weekend went - and stayed - well into the mid- to high-thirties (95+ for our American friends).

I can do that during the day, but I've never had to sleep in it.

We stewed in our juices. Not even enough wind to fill the wind scoop.

Somebody gave me the brilliant idea of throwing our comforter over the bow and then soaking it in water. The evaporation brought the temp down to a tolerable level for the second night.

I also used the transom canvas piece - with the big screen window - to fashion a screen door for the main hatch. Gonna buy a proper hatch screen.

But if I go out again for an overnight and the temp is gonna go into the 30s for the whole weekend, I'm gonna install an A/C.

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sailboatmike
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Re: I'm an A/C convert

Post by sailboatmike » Mon Jul 02, 2018 4:57 pm

I find the big thing on the X is to cover the front windows, they make the cabin like a greenhouse during the day.

I bought a car windscreen sun blocker and put it over the windows, the difference is astonishing. If you get really into it you can cover the side windows to, while the benefit is less than the front windows every little bit helps.

Image

I intend to get one of those cheapo Arctic Air things and give that a go in the coming summer, it runs off 12 volts or you could even run it off one of those phone charger battery packs for a couple of hours and by the YouTube reviews they seem to do a pretty good job for $35 worth a try

Image

DaveC426913
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Re: I'm an A/C convert

Post by DaveC426913 » Mon Jul 02, 2018 5:11 pm

sailboatmike wrote:I find the big thing on the X is to cover the front windows, they make the cabin like a greenhouse during the day.

I bought a car windscreen sun blocker and put it over the windows, the difference is astonishing. If you get really into it you can cover the side windows to, while the benefit is less than the front windows every little bit helps.
Huh. I would not have guessed that would make that much of a difference.

We've got white curtains covering the windows - top and sides. I wonder if a silver panel would improve it still further.

DaveC426913
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Re: I'm an A/C convert

Post by DaveC426913 » Mon Jul 02, 2018 5:18 pm

sailboatmike wrote: I intend to get one of those cheapo Arctic Air things and give that a go in the coming summer, it runs off 12 volts or you could even run it off one of those phone charger battery packs for a couple of hours and by the YouTube reviews they seem to do a pretty good job for $35 worth a try
Wondered how it could cool without an exhaust. But it's one of those evaporative coolers you put water in.

Those are dependent on humidity levels. Here's a (long-winded) review:
https://www.walmart.com/ip/As-Seen-on-T ... /601533073

They're also small enough that they'd be for personal cooling, rather than area cooling.

If you do get one, I'd be interested in hearing your review of their effectiveness in a Mac's cabin.

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Jimmyt
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Re: I'm an A/C convert

Post by Jimmyt » Mon Jul 02, 2018 6:16 pm

Not to discourage your purchase, but..

Evaporative cooling works best when you have a continuous supply of low dew point air. Where I live, the current dew point is currently about equal to the air temp of 76 deg F. At those conditions, you can't evaporate water into the air because it's already saturated. All the cooler would do here is move air.

In Reno, its 91 deg F, and 14% RH. The dew point is around 35 deg F. So, you can evaporate a lot of water under those conditions and produce considerable cooling - if you have a continuous supply of that low dew point air, a good size fan, and a lot of water to evaporate.

Evaporative coolers are generally operated as one-pass air systems, basically taking in outside air and then exhausting it from the space after the cooling effect takes place. If you recirculate, the humidity inside continually rises until the cooling effect can't take place. If I remember correctly, you can get about 1000 btu for every pound of water you evaporate. That small 6,000 btu/hr window unit from Home Depot would be matched by an evaporative cooler that evaporated 6 pounds of water per hour. Based on the water reservoir in the arctic air unit, the capacity would appear to be minuscule.

Now, if you're in a boat on the water, there is a gradient of dew point from saturated right at the water surface to ambient at some elevation above the surface. Wind direction and velocity influence this situation. If you have still air, and you're at anchor and in a closed cabin, I'd estimate the cooling effect at approximately zero, particularly after any significant length of operating time.

Most folks either install marine ac or something like the following to achieve comfort aboard during hot weather.

https://m.youtube.com/watch?v=2AGnbt-KHYA

For those of you that live in low dew point areas, you could use evaporative cooling, probably with a 12volt fan, and 12 volt water pump. Just pump your lake water over an absorbent media matrix and blow air through it into the front hatch and let it leak out of the companionway.

whgoffrn
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Re: I'm an A/C convert

Post by whgoffrn » Mon Jul 02, 2018 6:41 pm

Just buy a cheapo 5k btu ac for 100 bux at Walmart.... and a harbor freight 2000 watt predator generator....I was stuck in that same heat this weekend and it stayed cool inside even when 95 outside ..... it's not all that hard to cut new hatch boards out of cheap plywood with a cut out for the ac.... I have 2 pieces one fits over the ac and goes just a few inches above it so that I can step over the whole thing without removing the ac and the other part obviously fits on top... all you need is a couple blocks of wood under the ac to keep it level or slightly tilted down.....easy 2 hour job at most and the predator engine is light quiet and powers it great

whgoffrn
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Re: I'm an A/C convert

Post by whgoffrn » Mon Jul 02, 2018 6:53 pm

Harbor freight has their predator 2500 generators at 349 right now but be warned its louder and heavier than the 500 dollar 2000 ....I just upgraded from a 2500 to the 2000 and very glad I did so much easier to lug up and down the steps and sleep is much better with it so much quieter

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sailboatmike
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Re: I'm an A/C convert

Post by sailboatmike » Mon Jul 02, 2018 8:47 pm

While I realize each to their own, I like keeping my boat as a sail boat and not a water winnebago. :P :P :P :P

If your draw air from the bilge it would be cooled by the =water around the hull before going through the unit, so that may add to the cooling ability of the swamp cooler unit, anyway we don't get a great deal of humidity this far south.

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Jimmyt
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Re: I'm an A/C convert

Post by Jimmyt » Mon Jul 02, 2018 9:44 pm

DaveC426913,

I get it. Hard to sleep while stewing in your own juices. :D I don't mind being in the heat all day, but I want to be cool and dry when I'm sleeping. Don't even ask about the admiral. If she had to try to sleep in 95degrees, I'd be a dead man, or wishing I was.

I'm hoping to get her to overnight this fall when it's good camping weather. Not ready to spend the boat buck for a generator and ac unit just yet. But if I want to overnight during summer it will be a necessity.

Jim

whgoffrn
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Re: I'm an A/C convert

Post by whgoffrn » Mon Jul 02, 2018 9:55 pm

A generator can be had fairly cheap .... I laid $150 used for my predator 2500 ....its not terribly loud but it is slightly more loud and more heavy than the 2000 ..... I've had 2 small generators a honda 2000iu a predator 2500 and now the predator 2000 and I know harbor freight gets some bad reviews but I can honestly say my predator 2000 is every bit as quiet as my old honda .....every once in a while they go on sale with a coupon for 400. But you can get a cheap used predator 2500 for cheap if wanting to be extra thrifty

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Gazmn
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Re: I'm an A/C convert

Post by Gazmn » Tue Jul 03, 2018 2:34 am

Be a Hero Cap’n...

Bubba A/C or Better 8)

Billy
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Re: I'm an A/C convert

Post by Billy » Tue Jul 03, 2018 7:18 am

First, this is not a commercial offer. If your serious about A/C on your X and want an easy way to do it, I may have an answer. I located an extra A/C box in my warehouse. It's precut PVC board, assembles with SS screws, and holds a 5000 BTU A/C. It slides into the companionway, bridges the cockpit benches, and includes companionway board. I was letting members have them at my cost. PM me if interested. (And I did ship one to Canada a few years ago.) There are pictures in the archives, just run a search.

I can identify with the 95 degrees. Summers in the Carolinas can be brutal. Even with A/C on my X, I sometimes use a silver tarp over the forward windows when tied up. It does make a difference.

Billy

vizwhiz
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Re: I'm an A/C convert

Post by vizwhiz » Tue Jul 03, 2018 8:00 am

We’ve bought meat a couple times from one of those companies that ships it to you in a big square thick-sided styrofoam cooler. I’m going to try my hand at making a bona fide redneck a/c unit with ice and a fan. We already run an O2Cool fan all night when sleeping aboard. If we can get the temperature down a few notches when sleeping aboard, it will extend our sailing, or sail-camping anyway, season by a few weeks on either end of summer. I won’t even try it in July and August. Too hot and not enough wind - it would be miserable all day AND all night! :(

For those who are looking at evap cooling or a/c units, what is your lake/water temp where you are sailing for the summer? There are some small cooling units that pump water up from 20 or 30 feet below the boat and pass it through a radiator of sorts in the cabin, fan blowing across radiator, of course. This would help a lot at anchor if you had a deep water lake that was cold down low, or if you are far enough north that the ocean water never gets very warm. Down here where we sail, the water heats up to 80 degrees, so it’s of no use to us.

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ris
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Re: I'm an A/C convert

Post by ris » Tue Jul 03, 2018 8:05 am

We bought a Billy box and a $120 5000 BTU AC and it works great on the MacGregor 26. We also have a Honda 1000 W generator is very quiet and powers the AC. When it is hot this is a great solution for sleeping comfortably on a boat. We did have to modify the Billy Box slightly as they keep changing the shapes of the 5000 BTU Air conditioner. We are still using the Honda and air-conditioner in our travel trailer as we visit the national parks in our cargo trailer converted into a travel trailer.

DaveC426913
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Re: I'm an A/C convert

Post by DaveC426913 » Tue Jul 03, 2018 1:44 pm

Thanks everyone for your input.

I just realized I have another constraint: the Admiral will NOT be able to navigate past an A/C in the gangway. It will have to go somewhere else.

Two choices I see as possibilities:

1. A portable unit that can be placed below, in some out-of-the-way spot, with a hose vent to the outside. I suspect it will be awkward and noisy. (Heh. Maybe we'll convert the virtually unused head into an A/C locker.)

2. A unit small enough to be deployed through the forward hatch and mounted there (either adjacent to, or on top of the hatch itself) while at-dock.

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