Marine Air Conditioners for Sailboats

[Jay Campbell]

Art: The Dometic soft start (also called smart start) capacitor "electric spike arrestor" (it's on their web site - about $300) is widely put in boats here in Florida, and reportedly works well. The technology makes complete sense. The true beauty of the LG and similar portable units is the price at $250 and that it works! I have lots of room in a 3 deck trawler, so I could see space being an issue on a sailboat, but cutting a hole in the hull for the vent doesn't trouble me at all. I assume if you found a unit developed for solar it's 12 v, but the inverter technology is well developed. However, there are lots of nay-Sayers when it comes to powering an AC with an inverter and solar. I had to push hard to get this done, and find the little LG unit on my own, but I have a number of folks nearby using them on boats now, and hear more and more of people that have been using them instead of window units. I nearly sank our boat when an AC water cooling hose broke 3 years ago - anything I can do to move away from water-cooled units is a good thing, as I see it. - Jay


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[zboss]

Originally Posted by Jay Campbell

We are testing and so far pleased with the LG portable self evaporating AC as replacements for our 5 MarineAir salt water cooled units (50' trawler). $250 at Home Depot or Wal Mart for an 8,000 BTU 8 Amp unit. Attachment 84931 here's a pic of one temporary installation, vented through a portlight, although we plan to install them in closet/cabinet space. Attachment 84932We have the battery bank/inverter and solar power to run one unit for 8-10 hours and recharge the banks the next day, but that's irrelevant to the use of these units as standard AC. Jay and Karen Campbell on Largo, Palmetto, FL


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Seriously, you could guy one of those every "hot season" and toss it away and still not reach the cost of a "marine" air conditioner after 10 years!

[Jay Campbell]

Exactly!! Disposable and it works!


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[Formosa Scott]

We currently have 2 portable ac units, a 12k btu and a 13k btu on our Formosa 51, the power draw is less than the marine and I am happy to do away with the large pump. On very hot/humid days they struggle to keep up but no more so than the 2 16k btu units they replaced.
We had a rv air on our trawler for 5 years and it still worked fine when we sold the boat. The first portable air on this boat was used when we installed it and it lasted over 3 years, the best part is when it went out we ran to Lowes and had a new one in very quickly.
The 2 hose units are better but can be an added challenge on the boat. Our marine airs were loud, these can be loud depending on which one you get so pay attention to that.


Scott

[ArtM]

Originally Posted by Jay Campbell

I nearly sank our boat when an AC water cooling hose broke 3 years ago - anything I can do to move away from water-cooled units is a good thing, as I see it. - Jay

I had a water cooled unit and, though I never had a problem with it, I just hated the design.

In fact, I find through-hulls of any kind undesirable. I don't really believe they are necessary, and just really don't understand why they are such a big part of the design of larger boats, which can easily carry freshwater for toilets and/or can electrically pump sea water into the boat, if needed, instead of opening a hole in the side of it. Diesel engines can be cooled by radiators, and avoid the whole nasty mess of the "sea strainer" and the risks that entails.

Anyway, off topic now. I'm excited about the prospect that solar-powered A/C is finally here. It is the last major barrier to widespread adoption of solar energy, and also removes a barrier from Cruising life for me, or more specifically for the people I would like to have with me.

[ArtM]

Originally Posted by sailcruiser

I'm interested to see as well. Mine vents to the companionway which is highly inconvenient.

I have plans to add a proper water cooled unit sometime soon. The 70# portable is just a bit cumbersome.
SC


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I had one of those LG units in an apartment. I think it's kind of ungainly for boat use, but if you have a spot for it then it can do the job.

The vent hose is designed to be the same size as a standard gas fireplace exhaust flue -- though, oddly, mine didn't come with a usable adapter to connect to the flue.

I'm betting you can find the parts you need with gas fireplace components, and/or possibly in the dryer components section of a hardware store.

[Canibul]

Our boat came with a 21 year old marine air conditioner by Rich Beers in Florida. I have no idea what BTU rating it is, there's no documentation on it. We've only used it when in marinas, of course, since it's ac and we don't have a generator. Well, we do have a Honda 2000, but as far as that aircon is concerned no generator. Well, it will cool our aprox. 400 sq. feet of boat interior eventually. If I let it run overnight it'll be cool the next morning. But it doesn't really keep up that well with the solar heating during the day. It's really noisy, which can be useful in a busy marina. White noise drowns out the neighbors.

Yesterday the cooling water pump quit. I took it off, and it's this really slick design by a company called March. Magnetically driven and coupled. Sealed up. Etc. I'm measuring a dead short across the two ac power wires. I looked up the pump on the internet and Defender has them for $ 230.

Then I read this thread, and did some measurements. I can fit a 12,000 BTU portable in the same space where the Rich Beers unit is. In fact, I could fit two in there. I might be able to fit a 14,000 BTU in. If not, there are other places on the boat I could put it. I am limited to 15.5 inches width where the present marine system is.

This is an interesting idea. It's more expensive than replacing the pump, but not by that much. And I would be able to get rid of two more through hull fittings in addition to the four I can close off after changing to Nature's Heads. I agree with minimizing the number of holes in the hulls. I think this Rich Beers setup is old technology. Parts are expensive.

[a64pilot]

The March pump is pretty much universal, there are other pumps, even can get a pump designed for a fountain for small ponds, but expensive is right, by the time I got my new marine AC installed with everything that I needed to buy, it is about 10 times as expensive per BTU than a window unit sold at Lowes.
Newer Marine AC's are very quiet though, new one I installed under the front berth and all you can hear is the air from the vent, can't hear the compressor at all.
Marine AC's seem to pull 1 amp per 1,000 BTU, the one I installed in fwd cabin is a 5,000 BTU and a little Honda will start it and run it easily, start up of course is the issue

[Canibul]

This one is definitely not quiet. In fact, we have to turn it off to have telephone conversations inside the boat. That's pretty noisy.
Installing a new marine air conditioner here would be an expensive proposition, with freight costs from Miami and import duties totally 46% of the value of the equipment. It's too big to come in by courier, and so that adds even more to the costs as there are now taxes on sea freight and even taxes on the sea freight insurance.

I could bring a portable ac in as checked baggage.

[valhalla360]

On the old boat (31 Silverton), we used a carry on:
- Worked great at night but at only 7000btu, it couldn't keep up during full sun.
- A bit of a pain as you had to pull it in and put it back out, every time the boat moved.
- Looks a little redneck.

On the current boat we started with a marine unit (plumbed to thru hull):
- Expensive.
- Getting rid of condensation was a pain (we have normally dry bilges, so relying on the bilge pump wasn't desireable and the condensator had to be cleaned regularly)
- Have to clean the strainer regularly if you get into weedy waters.
- Liquid cooling eventually started corrosion eventually.

Currently using a portable unit (like the picture from an earlier post):
- Needs an interior space to place is along with access to a window to vent it (we have that a lot of boats don't)
- Drastically cheaper than a marine unit.
- Eliminates issues with thru hulls and condensation going into the bilge.
- We got the single hose unit, which has the down side of venting cooled air from inside the cabin as exhaust air. This substantially reduces the effective cooling and dehumidifying aspects. They do have two hose units that use outside air. I would recommend them but know they are more expensive.
- The exterior redneck level is lower but if someone comes in there is still some.

If you have a clear roof area to place it, I would look into an RV unit. Obviously, if you take salt water waves over the roof on a regular basis, corrosion will be a problem.

Another alternative would be one of the split unit AC units but that is likely limited to boats with places to put the two halves.

Bottom line everything is a trade off.

[Brannick]

For a more DIY and less expensive option, consider the 5 gallon bucket air conditioner. If you have an inverter, a counter top ice maker can be had for $179 from Home Depot that makes 5lbs of ice.

A 5 gallon bucket, a fan and some elbow grease give you a portable unit that you can put anywhere on the boat you need, no compressor, no vents, reuse or dump the water over board when it's all melted and the only power drain is a 12v fan and the ice makings in the first place.

Instructions with video here.

[dergon]

A few years ago we retrofitted an A/C into our 1985 Tartan 34.

We went with a Cruisair 18000 btu model. It fit well in some open space beneath our V-berth and a short run of ducting put one vent into our cabin and another into the V-berth. It works wonderfully.

On the dowside it dd require 2 extra through-hulls for water intake and output.

Also, the strainer unit that comes with the unit was undersized and cheap plastic. We upgraded that piece of the unit.


So far so good. I sleep so well when we're tucked in at a marina with no wind. (On a ball or at anchor the natural air is enough). Also, it is reverse cycle and great for those October/November evenings (before we haul out on Lake Erie)

I absolutely, positively DO NOT regret it.

[Arthur Garfield]

Dergon-what did the crusair set you back ?

I am unable to reconcile costs of marine A/C units.plus the threw holes,plumbing,pumps.... My interest is turning towards modified residential units.This particularly with low EERP units that use similar amperages as marine.

My thought turns to how effectively handle condensation.

One handy thought I saw used in Mexico is to replumb condenser into pre-hot water(fresh water) holding tank to cool it off.Worked really really !

[Snore]

One of the few things the PO did was install a 7,000 BTU cruise air in my Tartan 33.

The unit is in he head, one duct blows into the vee berth, the other into the salon. When at the dock during the day, I can turn off the duct to the vee and send all the air to the salon. Even on a S Florida summer day, working on the boat is reasonably comfortable.

[Arthur Garfield]

I have a question-- Are your boats insulated? Upper hull,under floor decking and, super structure ?