Hi.

My liveaboard friends here in Miami are always complaining about their expensive ACs clogging up with marine life and/or breaking down.

I purchased a simple $200-300 unit from Home Depot, and it's been working fine for almost 5 years now. This is NOT a wall unit. It's on rollers, and I never have to move it.

The issues I've had with it are:

1. It takes up space in the rear cabin, especially the duct hose out the rear window. I taped insulation around the duct hose to cut the hot air it's transporting.
2. You have to strap it down. I did this with ratcheting straps.
3. It needs to drain either into a bucket or the bilge. (I use the bucket.)
4. In the middle of summer in the middle of the day, it won't keep the cabin cool, since these boats have no insulation. All other times/seasons it cools and dehumidifies just fine.
5. The ladies are not impressed, aesthetically, but then I use the entire rear cabin for storage anyway, so that's a non-issue.

For me the positives far outweigh the negatives so far.

A few items from our experience with a 1999 model using a built-in MarineAir 16KBTU/hr unit with water cooling:

1. Overall, we have been out cruising in some HOT conditions. Coming into a marina at 1500 with a cabin temp of 87, it takes over 3 hours to cool below 82. If the sun is still beating down on the boat, the A/C can barely keep up.
2. When you are in the South in the warmer months, remember that your uninsulated boat is sitting in water that could be 85F or higher.
3. With our aft cabin converted to a permanent 'garage', I removed that portion of the ducting to direct most of it to the main cabin.
4. We suffer from frequent water flow problems due to marine growth at the thru-hull.
5. If you add a thru-hull for a water cooled unit, try to arrange a T-fitting right after the seacock so you can remove a plug and plunge down from the inside to remove any growth. You will ship a pint or so of water before getting the plug back in, but that beats having to go over the side. I can't do that on my boat because of the placement of the seacock relative to the cabin sole liner.

Having said all that, we have some friends who lived aboard their C36 in our climate for many years, so somehow they made it work for them. Maybe David Power will chime in with his experience.

Larry -
We cruise in similar waters (our boat is out on the East End of LI); she came with an installed Cruisair AC/heat pump under the forepeak. Actually, though, when we were shopping for a C36 a few years back, AC was not on our list of "wants", and we chose this boat out of the dozen or so we looked at based on other factors. But I have to admit that its turned out to be a nice amenity, less for the AC (which we used only a couple of nights last summer) then for the heat pump function, as the latter allows us to extend our season out (our boat is far from home, so when we're there its usually for at least one overnight stay). I'm assuming the unit you are looking at is capable of working as a heat pump as well?
If you'd like, next time I'm out to the boat for winter projects (maybe next weekend) I'll try to get the model # for you and take some pictures of the installation. We've had no problems with it at all, although if I had to do the installation over again I'd make a change or two.

As Duane, we lived aboard our 36 for 9 years, until 2011, in southwest Florida. We also had a MarineAir 16,000 BTU unit. We would set it at 78 degrees during the summer. We would also make sure our hatches were covered and the shades dropped on the side. We eventually would put a shade over the boat because we would not go out in the summer months and wanted to keep the direct sun off the boat. With all that, on "hot" days we might heat up to 81 or so in the afternoon but it would cool quickly in the evening. Our only problem with water flow was in our strainer with mud and barnacles. We cleaned it once a month. We eventually had to replace the unit and got a Mermaid. It's 16,500 BTUs, and which has a better warranty. Both units have a dehumidify function when your off the boat for any length of time.

You will also need to consider how to deal with the condensation. Some allow it to go into the bilge. Living aboard and now, we tried to keep our bilge as dry as possible and used a "condensator" from Mermaid to remove the condensation through the water discharge flow. It can be used with most permanent units.

[QUOTE=2sailaway;20388]...I want to make sure I have a unit large enough to keep up, do either of you think that a larger unit would make a difference down there? I was looking to go with a 18000 BTU unit or even 18500 but I have concerns with short cycling up here in the NE...[/QUOTE]

Logically, if you have more cooling capacity, it will certainly help in a hotter climate. It will almost certainly draw more current, so be sure that the start-up current and running load are within the limits of your electrical wiring.

David mentioned a shade to keep the sun off and I believe that is a big key, especially if you will be in one place for a while. If we were going to live aboard down here, I would want more cooling capacity than we have, that is for sure.

Talk to the manufacturers about your short cycling concerns and see what they say.

I can't fault Ben's KISS approach, but have no experience with that solution. Good luck with your decision.

Another consideration is running the AC on the hook. There has been a lot of discussion as to wether or not the Honda 2000 can start the AC because of the draw demands. Once started, the Honda will run the AC. As for the MarineAir unit, it seems like it depends on the individual unit. Some will and some won't start up. Apparently, you can get a capacitor added to the AC unit to get it started. The Mermaid will start up. If this is a concern, check with the manufacturer.

[QUOTE=2sailaway;20388].
Matthew, I would love to see a picture of the install, was it placed under the v-berth? What would you have done differently given the chance?
[/QUOTE]

Larry - it is indeed under the V-berth. Will try to get some photos for you next weekend, and the specs of the unit (the manual is on the boat as well). Then I'll discuss the plumbing routing (not a big deal, but the location of the thru-hull for the intake could have been better thought out, but this won't make sense to you until you see the photos). Other than that, the installation works fine for us. Its ducted into the forepeak and the salon (we rarely have anyone sleeping in the aft "cabin", so its mostly used for storage) but the unit seems to do a more than adequate job heating or cooling all the interior in short order.

As I said, mine does NOT roll around. It is strapped down. It would take a 180 degree rollover to move it...but then I'd have several other issues to deal with as well. :-)

I installed a Marine air unit under the v-berth in my 1987 MKI C36.
1. removed the shelving unit and replaced with a louvered grill made using a teak grill kit.
2. glassed in a shelf under the v-berth for the unit
3. took over the thru hull for the head (you could put a tee in the line for the fresh water intake for the A/C unit. I hate the green water in the head so instead use the shower head to spray water in to flush the head. Keeps the algae from growing in the bowl.)
4. installed strainer and water pump behind port v-berth bin
5. ran outlet for cooling water through a thru hull above the water line on the stern side
6. ran duct through the hanging locker, with a splitter so one vent went out into the v-berth and the other went through a round hole in starboard bulkhead, through the cabinet and then vents out into the bookshelf area
7. ran duct through the port head cabinet (tricky) cut round hole in port bulkhead, though cabinet and vented out into the bookshelf area (would not do this again)
8. I ran a separate A/C circuit for the air conditioner. In hindsight I would use the house A/C circuit instead, adding a separate breaker for the air conditioner on the panel. Then I would use the extra shore power outlet for the battery charger. Mostly to keep the wiring runs simpler. The charger and the air conditioner were a higher load than a single shore power cord was rated for.

One of the problems I encountered is after a pretty good sail in a stiff breeze running heeled over the cooling system would lose it's priming and I would have to put a garden hose in the through hull and re-prime the system.

When new it would drop the cabin temp pretty nicely in the evening. Key was getting the sun off the deck. I have a tarp that goes over the boom and ties to various rails and shrouds that works nicely. Also known to get the hose and wet the deck down to take the heat out of it. Amazing how much heat a FRP deck can hold.

I hate the condensation from the A/C unit going into the bilge so run it into a bucket that i empty manually. Pain.

We use the v-berth for sleeping and the unit would freeze us out. In summer it was comfortable in the cabin when at the dock in the evening. With a fan running the rear berth was comfortable as well.

Make sure the unit you get has ports for recharging the refrigerant. You won't care for a few years but if it doesn't then you can't recharge without a lot of rework.

A friend of mine made a plywood cut out for his Pearson companionway and puts a $150 window unit in for sleeping at night. works.

Thanks for contributing such detailed info, Brent. Your experience with the cooling capacity needs to be augmented with WHERE your boat was/is located.

How about adding a signature line with more info about your boat and locale?

Thanks!

Brent
Can that A/C unit be run on a 2K generator while on anchor or does in need to be used at a dock power only.

[QUOTE=2sailaway;20388]

Matthew, I would love to see a picture of the install, was it placed under the v-berth? What would you have done differently given the chance?
....[/QUOTE]
Here are some pictures I took today of the installed Cruisair heatpump/ac on our Mk I. As I mentioned earlier, this had been installed by a prior owner.
#1 is the air outlet in the salon, on the starboard side
#2 is the air outlet in the forepeak. The ducts to both of these are run in the hanging locker (the photos of the ductwork will be attached in another posting)
#3 is the control panel, on the starboard side (near the game table)
#4 shows the air intake grille, which replaced the hamper bin on the starboard side of the forepeak (all the drawers are out as well for the winter, so you can see the water intake, which is below the bottom drawer -- not a good location, but I'll discuss that later).
#5 is the heatpump unit itself, just in front of the drawer unit in the forepeak, under the bed. The water discharge goes off to the left (shown in a later photo). Would like to add a 3d water tank forward of it at some point, but it would be rather tricky (right now we store swimming floats and other light stuff under there).
To be continued (the site only allows posting 5 shots at a time)

[QUOTE=Chachere;20472]Here are some pictures I took today of the installed Cruisair on our Mk I. As I mentioned earlier, this had been installed by a prior owner. [/QUOTE]
Continuing... here are some photos of the ductwork
#6 - ducts leading from the unit
#7 - ducts entering at the bottom of the hanging locker
#8 - duct in the hanging locker connected to the back of the outlet grate that serves the salon (see photo #1)
#9 - duct in the hanging lockerconnected to the back of the outlet grate that serves the forepeak (see photo #2)
The ductwork does eat up a bit of space in the hanging locker, but its still useable.
To be continued ....

[QUOTE=Chachere;20473]Continuing... [/QUOTE]
Lastly, some of the plumbing
#10 shows the intake water connection to the through-hull, located underneath the drawer unit in the forepeak (the drawers are all out so you can see straight down in the photo). This is a somewhat mickey-mouse set-up, IMO, that includes an elbow apparently machined out of a block of bronze, and a (non-marine) ball-valve used as a sea-cock. This was apparently done because there was no room under the bottom drawer for a normal sea-cock, but I don't have much confidence in that ball-valve (you can see the handle is already rusting), and next time the boat is out of the water I intend to close off this through-hull entirely, and instead tee the intake supply into one of the lines served by the sea-cocks in the head (that certainly would have been an easier way to do this in the first place, and since the unit is only operable when we're on dock-power, I'm not concerned about heeling)
#11 shows the area to port of the drawer unit under the bed in the forepeak. You can see the intake run to the strainer, thence to the water pump, and then to the heat-pump unit. I added a tee with a plug so that I can temporarily screw a hose in to pour antifreeze for winterizing. I also have added a bracket for a false floor that normally covers this area, so we can use it for storage.
#12 shows the output hose run to the sea cock for discharge; its just above the waterline. I was rather surprised when I got the boat that there was no seacock on the discharge, just a cheap through-hull that the installer had not even bedded (duh-oh). I glassed in a backing block, replaced the through-hull and added a sea cock.

Other than these small installation issues, the unit itself has worked flawlessly. Although we don't often use it, when we do it makes our boat very comfortable, and very quickly. No condensation issues.

sorry I missed this thread last year.  Just an update.  I happened to catch the marina air conditioning repair guy working on a drop in unit in the driveway of the marina shop.  He does this full time, year round and usually has a waiting list of jobs.  Stopped in to chat and he shared a few pointers:

1.  Home Depot sells an air conditioning coil cleaner that removes the dust coating on the coils and improves the heat transfer.  Be sure and get the indoor not outdoor type.  The growth of mold and dust on the coils can have a huge impact on heat transfer and compressed air cannot remove it all.
2.  The old mechanical thermostats lack a defrost cycle so, the newer digital ones have this.  He recommends a few minutes each hour to deice the coils. Adding digital controls is so expensive you might as well drop in a new unit that comes with the new controls.
3.  Don't put pressure gauges on your unit unless you have to. Instead measure the temperature drop between the intake and air output.  A 20 degree drop is great.  Units needing recharge will be 8 degree drop or less.  Putting a gauge on the unit will inevitably cause a loss of gas no matter how careful you are.  Units before about 2008 are mostly R-22 which currently is costing $50 a pound.- even though the typical marine unit only holds about 21 oz you are going to get charged for a pound.
4.  Cooling output is inversely related to the intake water temperature.  At 90 degrees and above 'forget about it',  Somewhere on the Dometic site I found a pdf that gave the output based on the intake water temp and the btu difference between 85 degrees and 70 was huge.  That said our summer water temps are around 85 and the 16k unit does a good job of cooling the main cabin.  I can close vents in the head and v-berth to direct the cooling.  At night you need a blanket in the vberth.

i've often wondered if you could put a 'y' valve and an extra hose on the cooling intake that you could run overboard and weight it down below the thermocline.  Even in summer when the water is 85 it's a lot cooler if you go down about 10'