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I’ll keep an eye on this thread.
I have a 16000 btu Mermaid of unknown vintage (guessing about 15 years old; I’ve had the boat for 10) that probably needs replacement. 2 years ago it wasn’t cooling and local HVAC shop that seems to be the go-to for marine systems took it out, sent it to Mermaid and new compressor installed.  I paid Mermaid direct for compressor and freight. (internal short was diagnosis)

Worked in A/C mode last season, but heat mode didn’t work well at end of season. Hasn’t seemed to cool well this season. Had HVAC folks look at it a month ago, they diagnosed stuck reversing valve and got it to pump heat and cycle back to cool. They were going to check refrigerant level but found caps on ports were glued on. Not sure with what as applying heat did not break them free. 

I would NOT recommend Mermaid. Less to do with reliability as I recognize unit is up there in age. Not sure why they would seal service ports other than to require another round trip between WI and FL that is neither cheap nor convenient. Mermaid wouldn’t talk to me and both the service tech and owner of the business said they were kind of rude and condescending to them. 

I think ballpark estimate for new unit installed was around $3K. Forget what brands they handle but I’ll try to remember to look it up tomorrow. 

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I'll be keeping an eye also.

IIRC Dometic and Marine Air are the same units and parts.  Which I think really only leaves Webasto.  Good units from them too.  But, I find Marine Air to be the most common in boats I look at.

Curious to know if you will run it dockside only or if you have a genset,  If yes on the gen, what did you fit?

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8 hours ago, Hitchhiker said:

I'll be keeping an eye also.

IIRC Dometic and Marine Air are the same units and parts.  Which I think really only leaves Webasto.  Good units from them too.  But, I find Marine Air to be the most common in boats I look at.

Curious to know if you will run it dockside only or if you have a genset,  If yes on the gen, what did you fit?

Depends on the output of the generator and load requirements of the appliances you are running off of it. 

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The boat doesn’t have a generator. It will be a liveaboard at a marina with shore power.

I have 2 marine air units and a Fisher Panda generator on my boat. I’m looking towards the Dometic turbo like Will suggested.

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The previous owner of our boat installed a Flagship Marine FM18R. My understanding was the build quality was on the higher end, size on the smaller end and generally uses less wattage than comparable. My only two complaints is it doesn't seem to have a dedicated dehu mode and I don't love the rather large controller.

It cools our 42' boat well. 

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The HVAC shop I use handles Cruisair.  Which was purchased by Dometic a number of years ago.  I guess they finally retired the Cruisair name.  As pointed out, Marine Air is also under Dometic ownership.  

There is another company, FL based, with very similar name called MarinAire.  Don't know anything about them other than from their web page.  Seem to be relatively new (2007).

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I did see the Cruisair 18,000 as well. I just found suitable space under the nav station seat Aft with a deep well under it near the keel sump to drill a through hull water intake and condensate drain. On my 42, the a/c unit is under the forward bulkhead seat with space to spare, but his model has the forward house battery in that location and has no other place to re-locate.

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On 8/10/2020 at 5:13 PM, Sail4beer said:

Looking to install an a/c unit in a Catalina 42 this month and was wondering who like what and why. 
 

We have a Flagship Marine FM18 (might be wrong about the letters, but 18k btu). It works well and seemed to be compact and efficient. Previous owner put it in and we haven't used it in a year. Only complaints are the size of the control panel - it's like a 10" diameter, and the condensate collection and pump is in an inconvenient place, which I think may be an installation choice.

 

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I replaced an older Marineair unit with a 16,000 BTU Webasto unit.  Has worked well though the unit sometimes (I can't predict when) runs substantially past the thermostat setting.  Any advice there is appreciated.  Webasto has recommended moving the temperature sensor to focus on the return air but I haven't seen much improvement with that approach. 

One note - Webasto stresses switching the heating / cooling reversing valve every month to keep it lubricated and functional.  Even in the summer, I try to move the system to heat mode briefly on occasion and then switch back after a few minutes.  Same but opposite in cooler months. 

 

 

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  • 2 months later...

I installed 16000 Btu/h Self-Contained of Marineaire to replace a Dometic 16k unit in my 1989 Carver. The installation was pretty easy with all parts except the air splitter being a direct fit. The unit cools very well and is quieter than the original, it also draws less power and is 10-15 pounds lighter. A great money saving retrofit that's highly recommended for older yacht owners.

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On 8/10/2020 at 5:13 PM, Sail4beer said:

Looking to install an a/c unit in a Catalina 42 this month and was wondering who like what and why. 
 

A/C equals condensation 

like a mini water maker 

think of this when locating and installing the system 

Stagnant bilge water  and  mildew from a poorly , installed , located   AC makes the boat stink like a British pub carpet

ac uses plenty of seawater for cooling 

choose an oversized sea strainer 

if possible discharge the cooling water on the side of the boat , bootstripe ....away from the dock 

on many boats this means port side 

discharge on the dockside  is noisy when magnified by the dock 

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I had a Cruisair on my Hinckley, and have dual units on Restive. No probs with either.No gensets, they run of shore power. Interestingly, they will also run off the alternator, as we proved on particularly brutal afternoon, where it made supper tolerable. Sun went down, turn it off.

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Frigomar do a great inverter system. No startup surge so you can minimise genny surge, or maximise shore power without tripping. You can also turn it down if shore power is having trouble or you are on a different dock. Won awards at METS the other year.

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The companionway window unit setup is popular with racers who want to keep their boats cool and dry inside, but be able to take the weight off the boat when they are racing. Another option is thru the forward hatch, which is more out of the way.

Self contained units are good retrofit, but having the compressor in the cabin is noisy. having a split unit you can put the compressor in the bilge or cockpit locker somewhere. 

Make sure you mount the pump and inlet well below the water line. I was on a boat where the pump would lose prime every time we went sailing and heeled the boat over. So we either had to remember to close the thru-hull or re-prime the pump when we got back to the dock.

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The Marineaire fit on a marine plywood base under the settee as with my own boat and I was able to line up the port side bootstripe for the water discharge. There wasn’t much room for error. 
I used a welder’s hammer to screw it into the hull since it was such a good fit.

The air handler disconnects so the unit can fit in a tight space. The only problem I had was that the air handler wouldn’t spin once I wired the unit and powered it up the first time. I had to remove it and disassemble the blower housing to straighten the fan-which looks like a hamster wheel- it was off balance and rubbing against the inside of the housing. I got it centered and spinning freely, re-installed and it fired up properly, ran quietly and cooled the boat from 88 to 72 in a few minutes. 

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  • 1 month later...

I had a Cruisair stowaway turbo (16000 BTUs) go bad after many years of good service. Was considering purchasing one of the newer Dometics, but have heard quality of their units has reduced in recent years.

I was between choosing a Webasto FCF and a CTM unit, and decided on the CTM. Buddy of mine installed one early this year, and is content with it. Low price point, solid looking unit, good replacement option for cruisair (I was able to use the same SMXir control from my cruisair). https://citimarinestore.com/en/ctm-marine-air-conditioners/11908-ctm-ct16-16000-btu-marine-air-conditioner-115v-24101c.html

I like the titanium coils. My cruisair's compressor actually failed because of a hole in the rusted condensing coil.

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On 12/15/2020 at 10:25 AM, ryley said:

You might look at Phil's website

 

https://boatrx.com/how-it-works/

I studied that option before buying the CTM. However, with the CTM I added a soft start from micro air and the amperage drawn is minimal. My 3.5kw generator starts it without a problem and regular running amperage drawn is no more than 10 amps with 16,000 btu capacity. That small 12 VDC unit is only 7,000 btu and the amperage consumption is pretty high, so I would have had to change my whole battery bank system and the unit itself is over $5,000. Also, I read in other blogs that the control box runs very hot, close to 120 Fahrenheit, have you seen that issue?

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  • 7 months later...

Depends on your DIY comfort level:

1. Requires a thru hull (dedicated is best) for cooling water, and thru hulls (above the waterline) for discharge and condensation.  Do NOT use your bilge for condensation, you want a dedicated pump to push it overboard.  You may be able to "share" the inlet intake with something else, but dedicated is better, and as others have said, you really want it close to the centerline so you don't lose prime when you heel.

2. Requires below waterline plumbing (be sure to use the right stuff, else it might sink your boat if it fails and you're not there to shut off the seacock), and then outlet plumbing for the discharge and condensation.  For me that was a lot of hose!

3. Most require high voltage AC wiring, including dedicated shore power inlet, GFI breaker, galvanic isolator, and then AC wiring to the unit(s) and the pump(s).

4. Requires low voltage wiring of the control panel to a convenient location

5. Requires some ducting work, even if you're just dumping the output right into the nearest cabin.  Also needs decent return air volume, as if you don't have enough air flowing over the coils it will freeze up

I personally did a 2 unit setup (16k & 6k Marineaire) on my 41' boat.  One for the main saloon, with ducts to forward cabin and head, and the smaller for the aft cabin.

It was a decent amount of work, and last summer during COVID it was challenging to get some of the parts.  But it was LIFE CHANGING on the boat in the summer, as the removal of cabin humidity was the best thing ever.

So you need electrical tools, some woodworking stuff (to cut in registers) and plumbing tools, as well as comfort drilling holes in your hull and playing with AC power.

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I ended up installing a CTM unit myself this spring  Also included the soft-start/easy start controller.  I had the advantage of replacing a dead Mermaid, so wiring and plumbing/throughhulls were already in place.  Footprint and hookups had different geometry, so had to replace lines, add one or two elbows to avoid kinking water lines, adjust shelf height in the midship locker, and had a local HVAC shop fab a duct diffuser for recommended 6" and (2) 4" air vents.  You can also order them online or if lucky, Home Depot or the like may have one in stock that will fit.  My old air splitter would not fit. 

Replaced the 4" insulated flexible ducting due to unknown age/condition of existing ducting.  The wiring connections were a bit of a pain as busbar inside control box is pretty close to the wall of the enclosure and getting wires (especially 10g power wires) to fit neatly requires some planning and dexterity.  And the grounding screw is very short, so getting wires lined up and screw started in tapped hole was a challenge. Might be easier with an assistant holding wires with pliers, but had success after a few attempts by myself. 

But unit works vey well.  Cools/heats interior quickly.  Set to temperature and it alternates between cool and heat mode as needed.  Unlike most of the boats in our marina, I only leave the fan on when leaving the boat.  Most of the big powerboats have 2 or 3 A/C units and an icemaker running.  I have an aversion to pumping lake water into the boat when not nearby even though in theory it all goes overboard.  All my fittings are double clamped and I check them periodically, but you never know.....

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  • 3 weeks later...

I do not see much difference in these models; they are of the same class. But suppose you want that it serves you for many years and worked perfectly and flawlessly. In that case, you need to monitor its cleaning and regular filter change. Carry out preventive maintenance every six months, and everything will be fine. Without this, the service life will be reduced significantly. After a while, an unpleasant odor will appear. The air conditioner will become a breeding ground for bacteria and infections. But for real, the aircon chemical wash price is affordable. Don't skimp on your health.

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  • 2 weeks later...
On 11/8/2020 at 10:59 AM, jillyrubyjane said:

I installed 16000 Btu/h Self-Contained of Marineaire to replace a Dometic 16k unit in my 1989 Carver. The installation was pretty easy with all parts except the air splitter being a direct fit. The unit cools very well and is quieter than the original, it also draws less power and is 10-15 pounds lighter. A great money saving retrofit that's highly recommended for older yacht owners.

 

Hey Jilly Rubyjane, there was a time I tried doing this exact thing you did, but my colleagues were not buying the idea. They were trying to identify its faults even though it was evident that it is a more economical retrofit. It's been long tho so I can't clearly remember, but it was like I didn't try to use 16000 Btu/h; it was 24000 Btu/h I wanted to try. I even went to the extent of watching youtube videos to install it; I even had to ask these guys who call themselves the fastest service of a reliable aircon technician for some recommendations. But I still couldn't do it. It was hard to install, and as talking to you now, the boat has already been sold.

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25 minutes ago, Vin said:

We tried one, and it didn't work too well, as the cooling air for the compressor/heat exchanger is actually the internal air. So, while it's pumping in cool air, it's sucking in hot air as well.  In 100 degree heat it couldn't keep up. In 80 it seemed ok.

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The portable ones are very inefficient. That's why they have 2 ratings on the box; the nameplate rating and the "effective" (much lower) rating. Even the lower effective rating understates how bad they are.

Not only is the hot compressor and condensor inside the space you are cooling, you keep dumping all your cooled air outside as you use it to cool these components.

If you have a very small boat it might be good, but a good awning will do almost as much to cool the boat.

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16 hours ago, Vin said:

If you go that way, get one that has both intake and exhaust hoses. Eg. https://www.amazon.com/Whynter-ARC-122DS-Conditioner-Dehumidifier-Activated/dp/B01AA8WOAK/ref=sr_1_6?dchild=1&qid=1630652463&s=home-garden&sr=1-6

With only exhaust hose the unit will suck warm air from outside.

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  • 3 weeks later...
On 11/9/2020 at 4:19 PM, Mark Set said:

The companionway window unit setup is popular with racers who want to keep their boats cool and dry inside, but be able to take the weight off the boat when they are racing. Another option is thru the forward hatch, which is more out of the way.

Self contained units are good retrofit, but having the compressor in the cabin is noisy. having a split unit you can put the compressor in the bilge or cockpit locker somewhere. 

Make sure you mount the pump and inlet well below the water line. I was on a boat where the pump would lose prime every time we went sailing and heeled the boat over. So we either had to remember to close the thru-hull or re-prime the pump when we got back to the dock.

Dometic makes a hatch A/C (aka RV roof A/C) that came with my boat when I purchased it 3 years ago.  2 years ago I took it off because we couldn't stand not having good ventilation in the V Berth without firing up the A/C, plus: it leaked.  The proper hatch is much more user friendly, and easier to see around - that roof A/C was right in my sightline while steering.

Now I'm in the market to replace the dead watercooled unit that came under the V-berth, and at the moment my thinking is split between the Frigomar (if I can get it) for the low energy / crappy shore power friendly aspects, or the CTM CT-12 for the cheap aspects.   Somehow, the Dometic offerings fall in the middle, maybe higher quality / better customer service than CTM, but not really all that different tech/spec wise.  Frigomar is extra money, but how much is it worth to you to not have to go down the dock in the middle of the night to reset the breaker twice before deciding you'll be opening the hatches and installing the insect screens after all?

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