A/C for Venture 23.

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KevinMc

New member
Hi to all you Folks out there in Doryland,The weather is changing here in south Florida,I can now do some needed upgrades to Sea~Dory~Able.I was considering roof top A/C or the traditional water-cooled with through hull or a carry aboard.I did order a roof top unit but cancelled the order until I feel more comfortable with the options available.
I am concerned about the Roof top RV option due to righting moment and the extra 100+ Lbs so much above the waterline on an already tender boat.
I was also leaning (no Pun) toward the traditional water cooled marine A/C but finding the cabinet space is challenging what with the fresh water tank taking up most of the aft port side seating cabinet,which would be a perfect spot!There are some advanced new portables out there but still take up room and seem too tall to fit under the table,what to do?
I think the roof top option may be the best but all the reputable R/V units
(120Volts) may be too powerful at 9K btu and above for 104 Sqft / under 830Cuft. Any thoughts on the subject would be appreciated.KevinMc.P.s I saw Dr. Bobs' solution but will hold off on the roof hole for now.
 
Well "Dr Bob" has other solutions: one is the window unit. You will see photos in various parts of my photo album--specifically in the last 27, although we ran 5,000 BTU window units in both 22's and 25's we owned. Another option is the window unit in the door, with reflectix foil for the rest of the "door space. You need an extra fan to get the cold air up--since if flows downward. 5,000 Btu is marginal for the 25. We were in 106* at Benicia in the Sacramento Delta area. I had the Reflextix, cut out for the windows and doors, plus black out shades, and the window air conditioner got the temp down to 86--better than none. John in Cat o Mine uses a 15,000 BTU unit on his Tom Cat. I felt that the 9200 BTU unit was about right for the Tom Cat-

Any of these will run off Honda 2200 BTU generators, especially if you put an EasyStart or similar on to decrease the starting current. I had not measured the inrush--but it is close to locked rotor on most of these roof airs. Your point on the wegiht is well noted. We put radar arches, dinghies weighing close to 100 lbs up on the roof--etc--even a sun pad or a 2 room pop up extra stateroom (bunk for 2--probably in the 400 lb with two average adults in the bunk on a Venture 26. I know of a 22 iwth a sun pad where 2 gals sunbathed --maybe 300# total? But it is less stable.

There are several other options--one is the portable where you have to run the exaust, warm humidified air out a window or door. Usually this is the Port side widow forward--sort of interferes with the admiral/navigator, if they want to sit up there. We used one of these once--it was sort of a pain sitting in the Isle, fans to recirculate, and the exhaust warm air disposal.

Under the forward bunk is one place where you could put AC or 12 volt DC marine air conditioning compressor, usually the evaporator is somewhere you can duct air into the forward cabin and mid cabin. The condenser coils are. water cooled--also helps to cool the compresser. If you want to go 12 volt, I would count on at least 300 amps of Li Fe PO4 batteries to run the unit into the night.

What will you use to power any of these?
 
I go with the window AC option. My unmodified 5K BTU will run on a Honda 1000 generator. Since I only use the AC part time, having it removable is nice. I can leave it home when I don't need it. Being in FL might be a different story.

Disadvantage with the window unit is you can't really drive the boat with it in the window.

You might look at 12v RV rooftop AC units. Nomadic makes a unit that is less the 50#.

https://www.nomadiccooling.com/our-products
 
We used a portable window unit in our Venture 23. The only caution is the somewhat cumbersome difficulty getting it up and positioned on the deck. It worked great once in place, cooling the main cabin wonderfully. The one glitch was the cool air didn’t effectively drift forward into the v-berth area. To resolve this I used a short piece of the flexible 3” hose normally used to vent a dryer. I connected one end to one of the vent port on the AC unit and simply bent it downward 180 degrees so it was blowing into the V-berth. This worked wonderfully and didn’t noticeably diminish any cool air from the main cabin. You can see a photo of this in our Projects sub-album.

Rob
 
The reported weights between the 12 volt unit, and the 9200 BTU unit is only 30 lbs. The 9200 BTU costs 25% of the cost of the 12 volt unit. The 12 v. does not give BTU (that I have found yet). You probably going to want shore power or a generator running (although Li Fe PO4 batteries and a 2000 watt Victron multiplus (and a few others) would handle the load of the 9200 Coleman roof air. Plus the 80 amp battery charging required by a big "house bank" to give you cooling at night.
 
RobMcClain":3nvh541s said:
We used a portable window unit in our Venture 23. The only caution is the somewhat cumbersome difficulty getting it up and positioned on the deck. It worked great once in place, cooling the main cabin wonderfully. The one glitch was the cool air didn’t effectively drift forward into the v-berth area. To resolve this I used a short piece of the flexible 3” hose normally used to vent a dryer. I connected one end to one of the vent port on the AC unit and simply bent it downward 180 degrees so it was blowing into the V-berth. This worked wonderfully and didn’t noticeably diminish any cool air from the main cabin. You can see a photo of this in our Projects sub-album.

Rob
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I have a fan that hangs in the berth opening that blows the air from the cabin into the berth.
 
On the subject of fans--and they are as important in the PNW as in Florida".We have at least 4 Caframo fans through out the 22's and 25's. One on each side of the bunk to blow on the person in the bunk--one by the helm center and one aft blowing over the aft dinette seat. We also had a "Vantastic" RV fan over the forward hatch, similar to bathroom fans in RVs--usually 3 speeds, 5/8" dowel rods to rest the fan on--with flat places so they don't roll on the edges of the hatch--this is external to the screen or shade over the V berth hatch. The ones over the bunks have remote controls, so easy to reach in the bunk or from external, plus lights in the center.

We also carried a Ryobi fan which had its own stand, and would run all night on the same 4 or 6 amp battery. We would often put this by the opening window in the windshield when not using the AC. Also in my album are a number of tricks to using the fan: a block and tackle system to lift it in place, wooden runners, handles on each side, pool noodles and a skirt to seal the opening around the window.
Below is the Ryobi fan, Camfro fan
DSC00426.sized.jpg
Below is the spreader bar and block and tackle to raise the AC from under the bunk, to the window--hooking into the D handles in the 3rd photo. Also skirt around the AC.
DSC00478.sized.jpg
handles on the window AC unit.
DSC00451.sized.jpg


Windows have the reflectix Mylar/bubble wrap and black out shades to help heat gain or loss through the windows.
 
KevinMc,
When I got a 22, we did a lot of cruising and found that in the summer, we needed more comfort, on the hot muggy, windless days, specially when moored at a marina, which blocked any wind at all. Next we chose a simple window A/C unit, which worked well and kept us reasonably comfortable. The downside of the window unit, was installing it, after many hours underway, when I was tired and we were moored in the hot and windless marina setting. Several times, I almost slipped off the bow, just from sweating. Several times, I almost lost the A/C overboard, while on the bow...
Enough of that!
Next I installed a low profile A/C rooftop unit. No notable stability issues, we have cold air and we have heat, just a soon as it was plugged in. We absolutely loved this. The negative side of the rooftop is the noise that it makes. In the cabin, its just minimal white noise, but if you are on the adjacent pier, it would annoy anyone moored next to you. Knowing this, I always ensured that I moored as far from others as possible.
My 26 has a built in unit. No noise and very low power draw, much lower than the rooftop. The downside of the built in unit is that it is water-cooled, so using the A/C, while traveling on the trailer is no possible.
 
srbaum":1lvpqfxj said:
... Next we chose a simple window A/C unit, which worked well and kept us reasonably comfortable. The downside of the window unit, was installing it, after many hours underway, when I was tired and we were moored in the hot and windless marina setting. Several times, I almost slipped off the bow, just from sweating. Several times, I almost lost the A/C overboard, while on the bow...
...
Click to expand...

My window AC unit is installed in the window from inside the cabin. I don't need to go on the bow for anything related to getting the AC setup.
 
I am surprised that any put the AC in from the outside. Wooden runners on the bottom, which lock it in place on the lip of the window, with the block and tackle/and either anti slip mat or shop rags under the metal/wood when sliding it forward. This also allows you to keep the skirt attached, and easy to deploy.

Several boats put the window air conditioner in the starboard back window in the 22. Even in the door works in a pinch. (Like running the boat with window AC on.)

One other downside of the raw water cool marine AC is jelly fish will plug up the filter quickly--even a minnow will plug it up.
 
Thanks for all the suggestions,I am still mulling over 120V or 12V and combinations thereof. I did look at the split unit at 12V used primarily in tractor trailer cabs mounted in the cab rear wall with flexible hose line set.
Maybe mounting on the starboard outside bulkhead under the window and running the lines through the cable access hole under the gunnel and mounting the air handler / fan above the starboard window inside.Just thinking,I have not taken measurement at this point but will draw to scale and calculate needed amps.I do have 200 amp solar and two Lipo4 100 amp batteries (partially installed)not active at this time.I will do more research and consult the solar gurus.Please keep the conversation going.KevinMc
 
Just remember with a split is that the outside unit will be dumping heat. If this blows into the cockpit, it might make that area uncomfortable (especially on days where you need to use the AC). The other thing is that the split units come with fixed lengths hoses (usually something like 16ft). If you don't need that much run, you either have to store the excess somewhere or have custom hoses made.

I would put the outside unit on the roof. But then you might as well just get a roof AC unit.
 
I wanted to add AC to Full Circle for our Great Loop trip and did lots of research. We never got it done and suffered a little as a result. A rooftop unit was the easiest way to go, but our roof was completely occupied by the Roofnest roof tent with solar panels on top.

Nevertheless, I came across a couple of solutions that I liked which haven’t been mentioned here yet.

1: Dometic RTX 1000/2000 12V rooftop units. These are real AC units with efficient 12V compressors. Compared to 120V units, they are substantially lighter, quieter, and lower-profile. You’ll want 400-ish amp-hours (at 12v) of battery capacity and 400+ watts of solar if you don’t have a generator.

2: There are a few relatively new portable AC units that tick a lot of boxes for C-Dory cooling. My favorite is the new ZeroBreeze Mark 3. Think sewing machine-sized box with flexible ducts for intake/output air. 5280 BTUs, 22 lbs, 46 dbs, condensation drain pump. It’s 48v, so you either buy the battery packs that attach to the unit and charge them using 110v current when available, or you use your house bank and convert to 48v. Similar units are made by Bouge RV and Ecoflow. My measurements suggested that it would sit on top of the dash above the V-berth opening with the exhaust hose sticking out the center window and the cool air blowing into the cabin via the built-in vent or ducted into the V-berth at night through the duct hose. We fabricated a curtain for the V-berth opening. Poking the hose through the corner should allow the unit to maintain pleasant sleeeping temps using very little power. (The Mark 3 has a thermostat; the Mark 2 did not.)

Regarding rooftop units, I’m surprised any of them can withstand regular salt water baths. They are engineered to sit on top of RVs, after all.
 
Regarding rooftop units, I’m surprised any of them can withstand regular salt water baths. They are engineered to sit on top of RVs, after all.
_________________
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Interesting technology for the 12V and 48V units. It would be interesting to see how well they work.

The Army Corp of Engineers and many other work boats use the RV air conditioners. Some are a little more water resistant than others. We have never seen any decreased life span in these units. I suppose if the boat was getting regular salt water baths, then I would rinse the AC off when I get to an area where I had fresh water at the dock. I can only think of a very few times in the 20 or so years I ran C Dory's that i had salt water spray that was that intense. Once was on San Francisco Bay, and once was in Alaska, that come to. mind. Generally I would not have picked that kind of weather to travel--but SF was with the Delta Extravaganza. The other was because Marie was having too much fun catching fish, and the wind creeped up on us.

There are a lot of live aboards who put the RV AC unit over a hatch with seals for the "hot season"--and then take it off if going offshore--where sailing or big waves would cause problems. Plus under those conditions most hatches are closed.

We had an RV AC on the flying bridge hard top--and it worked very well--we closed up the clear vinyl windows and turned it on--would bring full sun temp of about 100 down to 80. About 20 degrees differential is about as good as it would get.

Many of our RV's are exposed to salt air--and it can cause corrosion on all parts of the RV.
 
As Bob stated there are units more suitable for saltwater use. After retiring for the USCG and taking care of at least 2200 small boats (boats less that 65'), I went to work for the Corps of Engineers and took care of their boats. I purchased and had many AC roof tops put on survey boats and had almost zero problems with them. They were all Coleman SeaMach/MarineMach 13500 BTU Air Conditioner, or similar in BTU ratings.
 
I wanted to add AC to Full Circle for our Great Loop trip and did lots of research. We never got it done and suffered a little as a result. A rooftop unit was the easiest way to go, but our roof was completely occupied by the Roofnest roof tent with solar panels on top.

Nevertheless, I came across a couple of solutions that I liked which haven’t been mentioned here yet.

1: Dometic RTX 1000/2000 12V rooftop units. These are real AC units with efficient 12V compressors. Compared to 120V units, they are substantially lighter, quieter, and lower-profile. You’ll want 400-ish amp-hours (at 12v) of battery capacity and 400+ watts of solar if you don’t have a generator.

2: There are a few relatively new portable AC units that tick a lot of boxes for C-Dory cooling. My favorite is the new ZeroBreeze Mark 3. Think sewing machine-sized box with flexible ducts for intake/output air. 5280 BTUs, 22 lbs, 46 dbs, condensation drain pump. It’s 48v, so you either buy the battery packs that attach to the unit and charge them using 110v current when available, or you use your house bank and convert to 48v. Similar units are made by Bouge RV and Ecoflow. My measurements suggested that it would sit on top of the dash above the V-berth opening with the exhaust hose sticking out the center window and the cool air blowing into the cabin via the built-in vent or ducted into the V-berth at night through the duct hose. We fabricated a curtain for the V-berth opening. Poking the hose through the corner should allow the unit to maintain pleasant sleeeping temps using very little power. (The Mark 3 has a thermostat; the Mark 2 did not.)

Regarding rooftop units, I’m surprised any of them can withstand regular salt water baths. They are engineered to sit on top of RVs, after all.
 
Dan, I'm new to this and I ask how do you plan get 400Amps to supply a roof unit without shore power? Can a standard battery bank supply this? I don't mean any disrespect, please forgive me if I stumble over this but a used medium age C-Dory 25 will be the most expensive thing (other than my house) that I'll ever buy. So the I don't want to muck up the looks of it by adding pipes, hoses and wiring all over the darn thing and I won't add something to a windows that bespeaks a 1950's Brooklyn garden flat. These Dometic 12V units that you refer to looks more factory built and clean and lean looking. But how to power it?




Full Circle":1bqrgkyu said:
I wanted to add AC to Full Circle for our Great Loop trip and




did lots of research. We never got it done and suffered a little as a result. A rooftop unit was the easiest way to go, but our roof was completely occupied by the Roofnest roof tent with solar panels on top.

Nevertheless, I came across a couple of solutions that I liked which haven’t been mentioned here yet.

1: Dometic RTX 1000/2000 12V rooftop units. These are real AC units with efficient 12V compressors. Compared to 120V units, they are substantially lighter, quieter, and lower-profile. You’ll want 400-ish amp-hours (at 12v) of battery capacity and 400+ watts of solar if you don’t have a generator.

2: There are a few relatively new portable AC units that tick a lot of boxes for C-Dory cooling. My favorite is the new ZeroBreeze Mark 3. Think sewing machine-sized box with flexible ducts for intake/output air. 5280 BTUs, 22 lbs, 46 dbs, condensation drain pump. It’s 48v, so you either buy the battery packs that attach to the unit and charge them using 110v current when available, or you use your house bank and convert to 48v. Similar units are made by Bouge RV and Ecoflow. My measurements suggested that it would sit on top of the dash above the V-berth opening with the exhaust hose sticking out the center window and the cool air blowing into the cabin via the built-in vent or ducted into the V-berth at night through the duct hose. We fabricated a curtain for the V-berth opening. Poking the hose through the corner should allow the unit to maintain pleasant sleeeping temps using very little power. (The Mark 3 has a thermostat; the Mark 2 did not.)

Regarding rooftop units, I’m surprised any of them can withstand regular salt water baths. They are engineered to sit on top of RVs, after all.
Click to expand...
 
I’m no expert on this stuff, so you’ll want to find a qualified resource to help you put this all together. But here’s how I think about it. Some of my assumptions may be way off.

The unit “amp-hour” represents an amount of current (amps) consumed in one hour. (Voltage is assumed to be 12V in this example.) The Dometic unit draws 20 amps in “Eco” mode, which would probably be adequate at night but not during the day. Its max draw is close to 60 amps. Let’s assume that its average draw during a normal day is 30 amps. An AC unit, like a refrigerator, cycles to maintain the set temperature, so it’s not always on; the “duty cycle” is less than 100%. Let’s say the compressor is running 50% of the time and you leave the unit switched on all day.

In 24 hours, the unit will consume 30amps x 24 hours x .5 = 360 amp-hours from the battery bank. That’s probably not feasible with solar power only. Another more likely scenario is that you only run it at night so you can sleep. 20 amps x 8 hours x .5 = 80 amp-hours. Your actual usage would likely be somewhere in between — maybe 150 amp-hours per day?

A larger battery bank allows you to go longer before the batteries are depleted, which is why I mentioned 400ah. That’s 2 - 200ah lithiums, which would fit easily in a C-Dory. But you DO have to replenish that lost energy with some combination of solar, the engine alternator, a generator, or shore power. In a 12 volt system, that 150 amp-hours translates to approx 2000 watt-hours of energy consumed (150ah*12.6v=1890wh). A nominal 400-watt solar array is about all you have room for on a C-Dory, and it might produce 300 watts for 7 hours on a summer day, putting 2100 watt-hours back into the battery. This barely replaces what the AC used, and you still need to power all the other systems on the boat. So you’d either need to curb your AC use or find some more charging power.

This all begs a couple of questions: How often will you really need cooling when you’re NOT connected to shore power, and how do you feel about generator noise? Running air conditioning off-grid is still challenging — and expensive. In the end, it may make more sense to install a cheaper 120V rooftop unit and power it with either shore power or a generator.

Again - I haven’t done this yet, so some of my calculations could be off.
 
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