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Air Conditioning - $300....?

Manete

.
Feb 5, 2020
10
Catalina 30 MKIII Middle River
Okay - so this idea keeps running through my head this week. To install AC on a Catalina 30 is a significant investment and a major do it yourself project..... I’d rather put the money elsewhere and go sailing. What about a portable AC unit?!? There is a plethora of models available in the $300 range. So my thoughts....

These AC units range from 7k to 15k BTUs and I think 8k or 10k BTUs is ample for a 30 in the Chesapeake. These units range from 8 to 12 amps which works with the available 30amp service. A perfect place for the unit (they are all vertical) would be against the compression post and possible tied down with the lower bracket that holds up the table. These units are typically ~24” tall and if you remove the caster wheels I think it would even fit under the table when the table is in use. Some models even have the hot air exhaust on the side vice the back of the unit. When using the AC, you could run the exhaust duct out the ceiling port window above the compression post. The units have water containment units built in you empty periodically or you could run the water line around the corner to empty in the head floor drain or directly to the bilge.

Anyone see issues with this thought other than it’s February and I’m thinking of air conditioning? Thanks in advance!

Esteban
 
Sep 25, 2008
5,563
Alden 50 Sarasota, Florida
How much room would you be sacrificing in your boat which isn’t useable now? How much noise do these things make? Is this a glorified dehumidifier?
 

Manete

.
Feb 5, 2020
10
Catalina 30 MKIII Middle River
Size - 17” x 13” x 27” including the caster wheels which I would remove. I’d be okay sacrificing that volume in that location. Mind you, it’s not a permanent fixture so the unit could be removed for fall season. Typical 8k BTU units advertise a cooling capacity for a 300sf room and the customer ratings are very good depending on the make. Excellent point on the noise and I can’t find info on decibels. I do note there are no noise complaints on the ratings and most indicate they cool a bedroom. How much can go wrong here - $300?
 
Jan 7, 2014
90
Beneteau 45F5 51551 Port Jefferson
I used a cruiseair-carry-on on my 32 foot Ericson and it did a great job They fit over a cabin hatch . Cooled the whole boat down. The only downside was it was a bit heavy . They don't make them anymore. I still have mine, I'll be selling it as soon as I get around to it, my current boat has A/C.
Here's a pic of one


1580959955919.png
1580959955919.png
 
  • Like
Likes: Manete
Jan 24, 2017
440
Hunter 34 Red Bank NJ
Hi Manete,
So I have a Hunter 34 and its roughly the same square footage of air space as your boat and sail in New Jersey not too far from where you are. Started many years ago air conditioning the boat on hot humid days using a small 7500 btu window unit which was the best fit at the time back in the 1980s.
It basically just barely made it tolarable inside the cabin when temps outside was high 85 -95 and high humidity. Found the unit to be ineffective and in the way.

Things that you must take in consideration is that your boat is unlike a house and has no insulation from thermal heat gain. Therefore btu's are a huge factor.
Your boat is very much like a car, and heats up quickly due to all of the exposed surface areas such as Windows and decking surfaces. Boats also have lots of compartments that are not easily ventilated.

I installed a mermaid mk16 1600btu unit custom designed by me which was the largest unit i could fit in my limited space I have to work within. I believe the unit cost was approximatly $1600 six years ago. This unit has served me well, however on really hot 90 plus days and high humidity the unit cannot keep up.
I have to put up sun shades to cool the deck or close off cabin areas. Not to say that the unit doesn't work, it just struggles to keep up with the demand. The btu's generated from us inside the cabin and the sun on the deck surfaces along with no insulation, is just to much. If I were to due it over again I think I would have installed a larger unit or a second unit somewhere else on the boat. I also use small fans to help circulate air.

I also have a portable rolling 1200 btu unit that you mentioned that I bought for my basement office. I occasionally use it on the boat and vent the exhaust to a small hatch. Note that the exhaust vent duct on all of the units I have seen are not insulated and give off tremendous heat. I had to swap out my vent duct to a four inch insulated one to reduce the tremendous heat that was infiltrating back into the cooled space.
These units do work well , however when the temps get up to 85 plus with high humidity, it will not be able to keep up. Due to the Deck surface and no insulation within the boat will be its down fall. My unit does seem to work very well at night when the heat index is less. I some times turn off the main mermaid system at night to save the ware and tear on it. I'd rather replace a $300 portable unit then have to buy and replace my $1600 unit.

Anyway, my experience is that a portable Ac unit can cool the boat under normal conditions 80-90 degree days with low humidity. However when the humidity gets high and temps above 90 the unit will not be able to keep up.
Plus plan on a sun shade and having to section off areas of the cabin untill the sun goes down. If possible purchase the highest btu unit you can, you well need it on hot days.


Just a FYI last year a bought a car/ truck insulated windshield reflector shade and cut peices of it to fit my port lights, Windows, and hatches. This seems to have helped a lot with the heat entering the cabin. Small cost vs the benefit.

Good luck and I hope this helps
 
Last edited:
Jan 7, 2011
1,782
Oday 322 East Chicago, IN
I think a portable would cool the boat down considerably vs not having any a/c. I was going to throw a window unit in my companionway for days when the heat is unbearable.

neither is as good as marine a/c, but I think it would be better than nothing.

Greg
 
Nov 8, 2007
1,238
Hunter 27_75-84 Lady Lillie Sandusky Harbor Marina, Ohio
Hmmm... Our air conditioning on Lake Erie is anchoring out, and opening the forward hatch over the v-berth. We also rig a custom made canvas cover over our boom to shade the cockpit and cabin.

on the hot summer days, lake water is usually in the low 70’s. This water is passively cooling the hull. Then, the air on the water’s surface is cooled near the water temp. So the breezes that come in the hatch provide substantial cooling. A scoop over the hatch cover accelerates the breeze. The combined effect means we are seldom uncomfortable, even on a 90 degree day. Getting away from the hot, humid shore breeze and into the Lake Erie Island anchorages also helps.
 
Feb 20, 2011
7,260
Island Packet 35 Tucson, AZ/San Carlos, MX
Adding some insulation around the exhaust pipe seemed to help a friend's portable AC perform better.
 
  • Like
Likes: Will Gilmore

Jim26m

.
Apr 3, 2019
470
Macgregor 26M P Cub Boo Mobile AL
Okay - so this idea keeps running through my head this week. To install AC on a Catalina 30 is a significant investment and a major do it yourself project..... I’d rather put the money elsewhere and go sailing. What about a portable AC unit?!? There is a plethora of models available in the $300 range. So my thoughts....

These AC units range from 7k to 15k BTUs and I think 8k or 10k BTUs is ample for a 30 in the Chesapeake. These units range from 8 to 12 amps which works with the available 30amp service. A perfect place for the unit (they are all vertical) would be against the compression post and possible tied down with the lower bracket that holds up the table. These units are typically ~24” tall and if you remove the caster wheels I think it would even fit under the table when the table is in use. Some models even have the hot air exhaust on the side vice the back of the unit. When using the AC, you could run the exhaust duct out the ceiling port window above the compression post. The units have water containment units built in you empty periodically or you could run the water line around the corner to empty in the head floor drain or directly to the bilge.

Anyone see issues with this thought other than it’s February and I’m thinking of air conditioning? Thanks in advance!

Esteban
Esteban,
These units are basically spot coolers, originally conceived for cooling down a small area, usually at the expense of the other area where the heat gets rejected. If you can get a dual duct version which pulls condenser air in from the outside, then rejects the heat to the outside, you will have a much better result. There are other brands, but here is one you can get in dual duct; 12,000 BTU Dual-Exhaust Portable Air Conditioner with Remote Control in White - WHAP122AW

What happens with the single duct systems is, you pull conditioned air from your boat interior, blow it over the condenser coil, and exhaust it outside. Exhausting air out of your boat requires that makeup air be drawn in through various openings, cracks, drains etc. As noted above, when ambient conditions are moderate and dry, this system might provide some degree of comfort. But, when it's hot and humid outside, the makeup air getting pulled in will likely overwhelm the cooling capacity of the unit. The result will be a cool spot right in front of the unit supply grille, and a warm humid boat everywhere else.

If you want to do it on the cheap, a window unit in the companionway, or through a hatch is an alternative solution. That way, the hot side of the system stays outside of the boat. Having it in the companionway can be inconvenient, unless your companionway is wide.

I believe there are several portable units with dual ducts, or an adapter kit to convert to dual duct. If you could do a dual duct install, with insulated ducting, the portable unit might do the trick.

Be prepared to deal with 5-8 gallons per 24 hrs operation as far as condensate is concerned.

What's wrong with air conditioning in February? I may have to run mine today...
 
Last edited:
Oct 24, 2017
5
Catalina MKII Chesapeake City MD
OK I've seen people put regular house "window AC units" in the entry hatch and other places. Seems like a really bad idea and it looks like, well I won't go there. I've read a few articles about how poorly they work too.

I installed a Webasto 120v, 1200 lb retrofit AC unit in our 1991 MKII 30. I built a shelf and put the compressor in the locker across from the head and ran one vent into the V-berth and the other out the back of the locker to cool the aft aria. I used a blocked off pickup in the engine bay for the water intake and mounted the water pump and filter in the engine bay. I ran the water hose through the holding tank aria behind the head and under the V-birth back to the locker.
I saw a post, when I was researching this, where they installed the compressor under the v-berth aft of the forwarded water tank but I didn't have enough room for it there.
The kit comes with about everything you need for installation, hoses, clamps, vents etc. I think it ran about $1200 when I got it 3 years ago.
We used to dock our boat in the upper Chesapeake Bay aria until last year when we moved to NE Florida.
I have a couple of complaints, it's noisy and too much airflow into the v-berth. I have all but one louver closed so that helped. I plan on insulating the locker this spring to cut down on the noise.
The AC keeps the boat comfortable for weekends. I keep it in the low 70's so it helps a lot.
You can heat the boat with this unit too, it's a heat pump.
I didn't take any pictures but I plan on going up and doing some work on it probably next month after I recover from an operation. I'll see if I can remember to take some pictures and post them.
Hope this helps.

 

Jim26m

.
Apr 3, 2019
470
Macgregor 26M P Cub Boo Mobile AL
I guess beauty is in the eye of the beholder. In certain companionways, it seems to be ok. Not my install, but I've seen several similar that look acceptable and perform adequately.
IMG_1195.jpg


Just depends on what skills you have I guess. I suggested it primarily because the original post indicated he was looking for a low-cost solution. Obviously, a built-in Webasto heat pump should be a better solution; it just didn't seem to fit my interpretation of the original question.

Don't know his boat or skill level. Just tossing out ideas.
 

JRT

.
Feb 14, 2017
1,709
Catalina 310 211 RoseLeigh Lake Guntersville, AL
The previous owner of my first boat, O'Day 25, installed a small window unit in the aft bulkhead that vented and drained to the cockpit lockers. It wasn't what I would have done, but it worked for his needs to 'camp' on the boat at the slip and it proved to be nice when I was working on her on in the heat.


Personally after dealing with all the half baked 'fixes' on my O'Day 25 I decided we were only doing these things right. My Cataline 310 comes with an install AC system that also has head and is just wonderful. Happy wife loves it and we are going to carry a small portable generator this year for summer hot days to have a cool cabin while out on the lake away from the slip.
 

Manete

.
Feb 5, 2020
10
Catalina 30 MKIII Middle River
Esteban,
These units are basically spot coolers, originally conceived for cooling down a small area, usually at the expense of the other area where the heat gets rejected. If you can get a dual duct version which pulls condenser air in from the outside, then rejects the heat to the outside, you will have a much better result. There are other brands, but here is one you can get in dual duct; 12,000 BTU Dual-Exhaust Portable Air Conditioner with Remote Control in White - WHAP122AW

What happens with the single duct systems is, you pull conditioned air from your boat interior, blow it over the condenser coil, and exhaust it outside. Exhausting air out of your boat requires that makeup air be drawn in through various openings, cracks, drains etc. As noted above, when ambient conditions are moderate and dry, this system might provide some degree of comfort. But, when it's hot and humid outside, the makeup air getting pulled in will likely overwhelm the cooling capacity of the unit. The result will be a cool spot right in front of the unit supply grille, and a warm humid boat everywhere else.

If you want to do it on the cheap, a window unit in the companionway, or through a hatch is an alternative solution. That way, the hot side of the system stays outside of the boat. Having it in the companionway can be inconvenient, unless your companionway is wide.

I believe there are several portable units with dual ducts, or an adapter kit to convert to dual duct. If you could do a dual duct install, with insulated ducting, the portable unit might do the trick.

Be prepared to deal with 5-8 gallons per 24 hrs operation as far as condensate is concerned.

What's wrong with air conditioning in February? I may have to run mine today...
Excellent point on the dual duct version - looking into the unit you listed!

Esteban
 

Manete

.
Feb 5, 2020
10
Catalina 30 MKIII Middle River
Hi Manete,
So I have a Hunter 34 and its roughly the same square footage of air space as your boat and sail in New Jersey not too far from where you are. Started many years ago air conditioning the boat on hot humid days using a small 7500 btu window unit which was the best fit at the time back in the 1980s.
It basically just barely made it tolarable inside the cabin when temps outside was high 85 -95 and high humidity. Found the unit to be ineffective and in the way.

Things that you must take in consideration is that your boat is unlike a house and has no insulation from thermal heat gain. Therefore btu's are a huge factor.
Your boat is very much like a car, and heats up quickly due to all of the exposed surface areas such as Windows and decking surfaces. Boats also have lots of compartments that are not easily ventilated.

I installed a mermaid mk16 1600btu unit custom designed by me which was the largest unit i could fit in my limited space I have to work within. I believe the unit cost was approximatly $1600 six years ago. This unit has served me well, however on really hot 90 plus days and high humidity the unit cannot keep up.
I have to put up sun shades to cool the deck or close off cabin areas. Not to say that the unit doesn't work, it just struggles to keep up with the demand. The btu's generated from us inside the cabin and the sun on the deck surfaces along with no insulation, is just to much. If I were to due it over again I think I would have installed a larger unit or a second unit somewhere else on the boat. I also use small fans to help circulate air.

I also have a portable rolling 1200 btu unit that you mentioned that I bought for my basement office. I occasionally use it on the boat and vent the exhaust to a small hatch. Note that the exhaust vent duct on all of the units I have seen are not insulated and give off tremendous heat. I had to swap out my vent duct to a four inch insulated one to reduce the tremendous heat that was infiltrating back into the cooled space.
These units do work well , however when the temps get up to 85 plus with high humidity, it will not be able to keep up. Due to the Deck surface and no insulation within the boat will be its down fall. My unit does seem to work very well at night when the heat index is less. I some times turn off the main mermaid system at night to save the ware and tear on it. I'd rather replace a $300 portable unit then have to buy and replace my $1600 unit.

Anyway, my experience is that a portable Ac unit can cool the boat under normal conditions 80-90 degree days with low humidity. However when the humidity gets high and temps above 90 the unit will not be able to keep up.
Plus plan on a sun shade and having to section off areas of the cabin untill the sun goes down. If possible purchase the highest btu unit you can, you well need it on hot days.


Just a FYI last year a bought a car/ truck insulated windshield reflector shade and cut peices of it to fit my port lights, Windows, and hatches. This seems to have helped a lot with the heat entering the cabin. Small cost vs the benefit.

Good luck and I hope this helps
Sigh.... now I’m wondering if a marine AC system is worth the investment if it struggles in 90 degree + days. Maybe for cooling down the boat at night. Just how noisy are these things?
 

Manete

.
Feb 5, 2020
10
Catalina 30 MKIII Middle River
I think a portable would cool the boat down considerably vs not having any a/c. I was going to throw a window unit in my companionway for days when the heat is unbearable.

neither is as good as marine a/c, but I think it would be better than nothing.

Greg
Hey! My previous boat was named “Tally Ho!”
98CE55A5-B8B4-43D6-8BD5-A52B0AD14ACB.jpeg
 
Feb 20, 2011
7,260
Island Packet 35 Tucson, AZ/San Carlos, MX
Sigh.... now I’m wondering if a marine AC system is worth the investment if it struggles in 90 degree + days. Maybe for cooling down the boat at night. Just how noisy are these things?
As in the post you'd quoted, shade the deck and close off unused areas of the boat.
It won't be the perfect fix, but it's better than nothing.
 

Manete

.
Feb 5, 2020
10
Catalina 30 MKIII Middle River
The previous owner of my first boat, O'Day 25, installed a small window unit in the aft bulkhead that vented and drained to the cockpit lockers. It wasn't what I would have done, but it worked for his needs to 'camp' on the boat at the slip and it proved to be nice when I was working on her on in the heat.


Personally after dealing with all the half baked 'fixes' on my O'Day 25 I decided we were only doing these things right. My Cataline 310 comes with an install AC system that also has head and is just wonderful. Happy wife loves it and we are going to carry a small portable generator this year for summer hot days to have a cool cabin while out on the lake away from the slip.
Google a consumers report article on a comparison between a portable Honda generator and a Harbor Freight portable generator. Findings where really surprising and the price difference is significant.
 

Manete

.
Feb 5, 2020
10
Catalina 30 MKIII Middle River
OK I've seen people put regular house "window AC units" in the entry hatch and other places. Seems like a really bad idea and it looks like, well I won't go there. I've read a few articles about how poorly they work too.

I installed a Webasto 120v, 1200 lb retrofit AC unit in our 1991 MKII 30. I built a shelf and put the compressor in the locker across from the head and ran one vent into the V-berth and the other out the back of the locker to cool the aft aria. I used a blocked off pickup in the engine bay for the water intake and mounted the water pump and filter in the engine bay. I ran the water hose through the holding tank aria behind the head and under the V-birth back to the locker.
I saw a post, when I was researching this, where they installed the compressor under the v-berth aft of the forwarded water tank but I didn't have enough room for it there.
The kit comes with about everything you need for installation, hoses, clamps, vents etc. I think it ran about $1200 when I got it 3 years ago.
We used to dock our boat in the upper Chesapeake Bay aria until last year when we moved to NE Florida.
I have a couple of complaints, it's noisy and too much airflow into the v-berth. I have all but one louver closed so that helped. I plan on insulating the locker this spring to cut down on the noise.
The AC keeps the boat comfortable for weekends. I keep it in the low 70's so it helps a lot.
You can heat the boat with this unit too, it's a heat pump.
I didn't take any pictures but I plan on going up and doing some work on it probably next month after I recover from an operation. I'll see if I can remember to take some pictures and post them.
Hope this helps.

Believe it or not we actually make full use of the locker, so it’s not an area I want to give up. Always thought about the port locker for an AC unit but I just can’t wrap my head around how/where run ducting to include the v-berth....