Do RV rooftop Air Conditioners work well on boats?

[geoleo]

Jut wondering if RV rooftop style Air Conditioners work OK on boats?

[newhaul]

That is essentially what the cruiseair carry on is.
https://www.google.com/url?sa=t&sour...-DboaSRrEeVuji

https://www.amazon.com/dp/B0002YGIZ0...l_8iwt9qctmy_e

[valhalla360]

If you have the open rooftop area, it can be a nice option.

Not such a great idea on sailboats as the boom and various lines can snag on it.

The other issue would be if you are frequently out in big water taking waves over the cabin top. Some occasional light splashing shouldn't be a big issue as long as you rinse it out with fresh water (they are designed to live outside in the rain) but full on submerged as a big wave goes over the cabin top could be problematic.

[CaptTom]

I'd be concerned about the effect of salt spay, and even salt air, on them. I've seen all kinds of automotive-grade things corrode badly in a very short time.

Otherwise, they should work fine. There are reasons for using raw water as a heat sink; it makes the unit smaller and easier to tuck out of the way on a boat, plus being able to duct the air to where you want it helps. Overhead units can be uncomfortable to sit under, and I've heard condensation can drip from them. In theory, using water as a heat sink can be more efficient, but probably not enough to sway anyone's decision.

[Sailmonkey]

They work well on boats used as condos, or on lakes. However for boats that are actually used in the salt....not so much. Look under the cover sometime, they’re wide open electrically and mechanically. None of the materials are corrosion resistant when exposed to salt.

Yes they work in the rain and on RV’s but this is a completely different enviroment

[valhalla360]

Originally Posted by CaptTom

I'd be concerned about the effect of salt spay, and even salt air, on them. I've seen all kinds of automotive-grade things corrode badly in a very short time.

Otherwise, they should work fine. There are reasons for using raw water as a heat sink; it makes the unit smaller and easier to tuck out of the way on a boat, plus being able to duct the air to where you want it helps. Overhead units can be uncomfortable to sit under, and I've heard condensation can drip from them. In theory, using water as a heat sink can be more efficient, but probably not enough to sway anyone's decision.

RV's park on beach campsites all the time, so a little salt spray shouldn't be a big deal. Worst case give it a fresh water rinse occasionally. Full dousing with a wave crashing over the top though may be pushing your luck.

Getting rid of the thru-hull and associated plumbing is more than worth any hassle and at less than half the price, even if they don't last quite as long, you may still come out ahead replacing it every 10-15yrs.

If condensation is dripping inside the living space, there is something wrong with the unit or the installation.

Again, the big challenge is finding a location to install it.

[SailFastTri]

The only advantage is price. Water heat exchange is MUCH more efficient, and all the other negatives of an RV unit have already been mentioned. I also think it would devalue your boat (and junk up the look) if you installed an RV unit. (Just add a blue tarp cockpit tent to complete "the look").

[newhaul]

Originally Posted by SailFastTri

The only advantage is price. Water heat exchange is MUCH more efficient, and all the other negatives of an RV unit have already been mentioned. I also think it would devalue your boat (and junk up the look) if you installed an RV unit. (Just add a blue tarp cockpit tent to complete "the look").

hey now I use silver tarps as my dodger fabric. And white for boom tent.

[SailFastTri]

Originally Posted by newhaul

hey now I use silver tarps as my dodger fabric. And white for boom tent.

Hey, some people like the trashy look. Worn and torn jeans are fashionable, why not silver tarps?

[zeehag]

considering folks remove em to sail and reinstall em to sit at a dock in hurricane season, they seem to work nicely. they are made for the job, as opposed to a small window unit, and hold up better than window units.
keel cooled air cond units fail here in 85 f water, ours is to 100f in summer, when air is needed, with high humidity.
when you are repairing your boat in 100f air with 9900000 percent humidity, what will you do. your keel cooled air wont work, as the water under your keel is 100f, and you are not going to be able to effect many repairs without something. if an overhead hatch mount air is available, it is better than the alternative,. not permanent and is stowable.
oh yeah. the rigging of your boat does NOT interfere with the function and placement of the unit. i have seen more sizeable items sitting on top of folks's boats without incident... dinghies etc. and how is a stowed unit going to interfere with sailing.
so what are your real issues with this mode of cooling a hot boat???


oh. my silver tarps are green, and i use screens as tarps as well.... without shade, one dies in this almost tropical sunshine. gets warm and bakes you. tarps make a HUGE difference. about 10 f cooler under the tarps here. other boats --even snotty yotties use silver tarps here.
in a sea of silver tarps, green is a statement. you kids need something real to gripe and whine about

so much pure judgemental ism... good luck in real life with real issues.

[newhaul]

Originally Posted by SailFastTri

Hey, some people like the trashy look. Worn and torn jeans are fashionable, why not silver tarps?

it actually looks good.

[SailFastTri]

Originally Posted by zeehag

considering folks remove em to sail and reinstall em to sit at a dock in hurricane season, they seem to work nicely. they are made for the job, as opposed to a small window unit, and hold up better than window units.
keel cooled air cond units fail here in 85 f water, ours is to 100f in summer, when air is needed, with high humidity.
when you are repairing your boat in 100f air with 9900000 percent humidity, what will you do. your keel cooled air wont work, as the water under your keel is 100f, and you are not going to be able to effect many repairs without something. if an overhead hatch mount air is available, it is better than the alternative,. not permanent and is stowable.
oh yeah. the rigging of your boat does NOT interfere with the function and placement of the unit. i have seen more sizeable items sitting on top of folks's boats without incident... dinghies etc. and how is a stowed unit going to interfere with sailing.
so what are your real issues with this mode of cooling a hot boat???

Ha! zeehag, where do you have 100f water? Are you docking over a hot spring?

[rwidman]

While an RV roof top AC would "work" on a boat, simple observation of boats should tell you that most people opt for the traditional marine AC using sea water as the cooling medium rather than air. When you go shopping for a new boat and specify air conditioning, the manufacturer will use a marine unit, not a rooftop unit.

My point is, many people before you have come to the conclusion that the water cooled units give better performance than the air cooled RV units. If you have a reason to use the RV unit, fine but don't use it because you think it will be better in any way.

[valhalla360]

I think we need to clarify: You are talking about the CruiseAir carry on Units that fit in an existing hatch. We had one of those way back. It was better than nothing but not by a lot. Because it didn't seal around the hatch very well, a lot of the cooling was lost and it was only 5000btu to start (I think the new ones are 7000btu). It also had to be stowed and reinstalled every time the boat was taken out.

This thread is about a permanently mounted RV unit presumably mounted on a hard top above the salon. There are typically 15000btu, so they put out a lot more cold air. These will conflict with the boom and lines.

The guts are essentially the same and again as long as they aren't submerged by breaking waves, they should hold up fine (hence putting them on the hard top). On a later boat we had a water cooled Marine Unit that had corrosion problems, so don't count on them being a lot better made.

As far as the water temperature making a difference on traditional marine units, that is absolutely correct. There was a very noticeable difference in cooling power between the great lakes where at the peak of summer, the water might get up to the low 70's vs S. Carolina with 90+ degree water.

I can't find it but I know there was a trawler brand that offered them and they looked fine.

I suspect you don't see more because of some of the unsubstantiated ideas you are seeing on this thread.

Originally Posted by zeehag

considering folks remove em to sail and reinstall em to sit at a dock in hurricane season, they seem to work nicely. they are made for the job, as opposed to a small window unit, and hold up better than window units.
keel cooled air cond units fail here in 85 f water, ours is to 100f in summer, when air is needed, with high humidity.
when you are repairing your boat in 100f air with 9900000 percent humidity, what will you do. your keel cooled air wont work, as the water under your keel is 100f, and you are not going to be able to effect many repairs without something. if an overhead hatch mount air is available, it is better than the alternative,. not permanent and is stowable.
oh yeah. the rigging of your boat does NOT interfere with the function and placement of the unit. i have seen more sizeable items sitting on top of folks's boats without incident... dinghies etc. and how is a stowed unit going to interfere with sailing.
so what are your real issues with this mode of cooling a hot boat???

[smj]

Yes they absolutely work. We had a single RV rooftop 15 or 16,000 btu on our old 36' catamaran and you could hang meat in there on a hot humid Galveston summer day. The 16,000 btu marine unit wouldn't even remove the humidity.
A friend had his RV unit permanently installed on his 33' monohull which he routinely raced across the Gulf Of Mexico and he never had any problems with salt water intrusion.
But they can look a little funky......