Prairie 29 AC

straycat · Jun 5, 2013

We are in the process of installing air conditioning on Straycat. We have a 16000 btu Marine Air unit and are trying to decide where to install the thru hull and discussing how the discharge water will be eliminated. Some boaters simply send the water into the bilge to be pumped out by the bilge pump. Others have a direct line discharge overboard. Any suggestions or experience for the most effective cooling?
We are installing our unit in the "electrical" closet and would also like to know how or where other boaters directed the ac air within the salon/berth area.
We are really looking forward to using the ac here in Florida.....Can't come too soon for me.

DavidM · Jun 6, 2013

By discharge water, are you referring to the raw water or the condensate produced by dehumidification?

Raw water is always discharged through a thruhulll about 6" above the water line. Condensate is often dumped in the bilge or sometimes to a shower sump where it is isolated from the bilge and pumped overboard.

Somebody makes an aspirator type device that lets the condensate be sucked into the raw water discharge.

David

Sortie · Jun 7, 2013

Hi Straycat,

Our 16000 unit is installed on the Starboard side in the "couch" area. Cooling water is discharged overboard as described by David. Condensate is dumped into the shower sump. The unit works very well and is effective in the heat of a Fl. summer.
John

Baker · Jun 12, 2013

On my P29, the AC unit was in the hanging locker(same place you are referring to I believe) basically underneath the helm. The return air was in the companionway to the V-berth underneath the electrical panel and the cold air was discharged into the salon basically at the helmsman's feet. A 16BTU unit will still struggle in the heat of the day as the P29 has so much window area and open space but gets quite cold at night.

straycat · Jun 21, 2013

Sortie said:
Hi Straycat,

Our 16000 unit is installed on the Starboard side in the "couch" area. Cooling water is discharged overboard as described by David. Condensate is dumped into the shower sump. The unit works very well and is effective in the heat of a Fl. summer.
John

Thanks to all of you for your info. We have also considered placing the ac unit in the salon inside of a built in " seating area much like we had on another boat. If we leave it in the locker area, we need to run the ac air up higher then the floor of the nave station. Cold air falls and would not be useful from that area. We thought of running some oblong shaped ductwork through the storage area in the salon and up a wall to disperse the air.
If situated in a seating area in the salon, where did Sortie run the ac air to in relation to the air intake. They should not be located near one another or the unit will not work properly. Is your through hull located in the engine room area of the boat. We still need to get that installed as well.

As for the cooling water, we will also need to install a through hull for that as well.

Our condensate will flow into the bilge. We have a shower sump, but it needs to be turned on with a switch, not automatic....don't think I want to hear that constantly.

I assume that the ac unit in the salon would give greater cooling then in the electrical closet. Any photos of the install on your boat Sortie? Thanks again guys.

Sortie · Jun 21, 2013

Stray cat,
Yes it does work better when above deck. Will get some picture for you. We are presently on the hard for a bottom job. Hopefully back in next week.

John

straycat · Jun 23, 2013

AC. Thanks for the input. We hope the bottom job goes well.

Sortie said:
Stray cat,
Yes it does work better when above deck. Will get some picture for you. We are presently on the hard for a bottom job. Hopefully back in next week.

John

In this heat the job is a bear. Stay well, Rick & Donna

straycat · Jul 23, 2013

Wondering Sortie, if you have completed your bottom work yet. Would really appreciate some photos of your AC install in the salon. Where did you locate your through hull for the water supply, and raw water discharge? We are approaching the beginning of deciding the best area to install the unit. For the best results, my understanding is that the return air and AC air should not be located next to one another or on the same wall and height. Straycat has a propane heater located on the nave station, just below the electrical panel. Leaving the unit in the closet, our return air would be on the wall beneath the door. We would need to layout the AC discharge in a more central location. Friends of ours have the discharge overhead above the door, between the head door and the locker door. There is no unit on the boat now, so no idea how efficient the AC would work in that set up. Thanks again for the info from everyone.

Sortie · Jul 31, 2013

We have a set tee on the stdb. side It runs from the rear bulkhead to the area where the refer is located. After the refer is the helm station. The set tee serves as a couch and storage area. the fwd part is where the AC is located.

The area immediately behind the helm is a raised area for the AC duct work. There is a pipe running from the duct area to the fwd. cabin. We also have a grate that can be opened into the engine room in case you need some cool air.

We are happy with set up. It works well for us. There was some bad sub flooring in the main cabin, near the cockpit. As a result we redid everything inside, thus the different dinette and the set-tee.

John

straycat · Aug 1, 2013

Thanks a million. The photos and text are great help. You did a superb job in the renovation. We are printing out the photos to use in our installation.
Peace, love and joy, Rick & Donna, Straycat

straycat · Aug 1, 2013

Sortie said:
We have a set tee on the stdb. side It runs from the rear bulkhead to the area where the refer is located. After the refer is the helm station. The set tee serves as a couch and storage area. the fwd part is where the AC is located.

The area immediately behind the helm is a raised area for the AC duct work. There is a pipe running from the duct area to the fwd. cabin. We also have a grate that can be opened into the engine room in case you need some cool air.

We are happy with set up. It works well for us. There was some bad sub flooring in the main cabin, near the cockpit. As a result we redid everything inside, thus the different dinette and the set-tee.

John

What a great layout. Our boat has the galley on the port side which includes the refer.
However, the layout on the port side could be used for Straycat and the refer space utilized for storage. A few questions please?
Did you just draw a straight line from the left side of the nav station back to the door? Locating the exit ac as you have, do you have enough cold air? As it was explained to us, the duct work would be more effective exiting higher.
Looks as though the storage area for the AC is sound proofed. Like that it is separate from the storage area.
What did you do with the storage area remaining under the wall on the port side? At the moment, we have access to that area by removing panels attached located at the base of the starboard wall.
Where is the thruhull for your AC located? Our our autopilot is located, at the bass of the head in the berth area, we will need to position it, the pump, in a different location since it is magnetic and would interfere with the autopilot. Thanks again! Donna

CaptTom · Aug 1, 2013

I recently added AC to the Prairie 29's big sister, the 36. The actual locations won't help you, but here's two things I learned that might:

1) The Saloon is like a greenhouse. I'd say 80% of the cooling needs are there. I knew this would happen, but I'm still amazed how much solar heating the big side windows and doors introduce.

2) Tape or hang the thermostat in different places and try it out in different heating/cooling modes for a while before drilling any holes to mount it permanently.

straycat · Aug 1, 2013

Thanks for the advice. Our side windows do slide open and we have no helm door, but do have the aft door and without ac, we use a screen that snaps in place, also added by the former owner. To this I added a long zipper across the top and down one side to allow easy egress of the doorway. I used a sleeping bag zipper which has a tab on both sides of the zipper.

We also, thanks to the former owner, have two canvas roll up awnings one on each side over the big windows, which we always use at anchor. They make a huge difference with the sun. We also keep the windows open when it rains as the awnings keep out the rain in all but blowing conditions.

The former owner had custom drapes installed which help with the heat accumulation. Of course, we may only use the ac at night to sleep, but it would also be nice to derive comfort during the daytime if necessary.

We really appreciate all the advice and will work this into a plan for our boat. Do you have your delivery ducts located up high? Donna Cass

Sortie · Aug 1, 2013

Donna; Lets see if I can answer your questions. Basically I did draw a straight line for the set tee. Our layout is the galley to the port side, but not along the entire side. Our sink runs port - stdb . There was a overhead storage cabinet which we removed. The original dinette was a U shaped area with a table and storage underneath . This was the area of bad sub flooring. This dinette was replaced with a traditional dinette arraignment. Consequently we lost that storage under the port side decks.

The storage under the set tee is a great addition and the area is separate from the AC, which is yes insulated. Directly below the storage area of our set tee is the location of the gen set, so that area is also insulated.

The best AC is to get the duct work exit as high as possible. We struggled with this, decided that we wanted the clean look as much as possible. Our cabin door was in bad shape, and was replaced with a custom made thick door that provides much better insulation against the heat/cool. Our windows were even in worst shape with lots of leaks. We replaced all windows with tinted window, much tighter fit, resulted in fewer air leaks and no water leaks. We add a heavy gauge privacy screen on the outside windows and heavy drapes with lining to protect against the sun. The results are dramatic in making a cooler area. It worked well and we are pleased.

I agree with Capt. Tom, play with the placement of your temp equipment looking for the right combination. Your right the cooling does not stretch back to the stern as well. However, the new door and the cockpit cover help a lot. The cockpit cover can be left as a shelter or raised as a Bimini cover. Our thru hull fitting was already located in the area near the engine thru hull, just fwd. of the engine near the stdb. stringer.

Hope this helps. Thanks for the kine words regard the result. It ended up being more then I originally thought. We are very pleased and love our trawler.

John & Sue.

CaptTom · Aug 2, 2013

Donna:

I like the idea of roll-up awnings! Just last night I went to sleep with all the hatches open, knowing I'd have to wake up to close them when it started raining. I'd like walk-around, permanent awnings like I've seen posted here (sorry, forget who) but they'd have to be halfway up the flybridge side and that would look stupid.

We just bought a commercial-grade sewing machine and enough fabric to do window and door coverings all around, as well as two types of screens (the fine white mosquito netting type and the normal window screen grey stuff). We already installed cellular blinds on all the windows but the front. They do help, but I think having something on the outside will help more.

The genset that came with this boat is a 7.5KW diesel that's bolted right to the stringers. It really rattles your teeth, and I'm hoping not to have to sleep with it running very often! So "breeze management" is pretty high on my list. I've even been looking at those breeze catcher hatch covers that the sailboats use a lot.

Oh, and the ducts are up as high as they'd go, but still only half-way up in the saloon. The diffusers point up and down, so that helps keep the air circulating a little. I've had good luck running a table fan, too.

straycat · Aug 2, 2013

CaptTom said:
Donna:

I like the idea of roll-up awnings! Just last night I went to sleep with all the hatches open, knowing I'd have to wake up to close them when it started raining. I'd like walk-around, permanent awnings like I've seen posted here (sorry, forget who) but they'd have to be halfway up the flybridge side and that would look stupid.

We just bought a commercial-grade sewing machine and enough fabric to do window and door coverings all around, as well as two types of screens (the fine white mosquito netting type and the normal window screen grey stuff). We already installed cellular blinds on all the windows but the front. They do help, but I think having something on the outside will help more.

The genset that came with this boat is a 7.5KW diesel that's bolted right to the stringers. It really rattles your teeth, and I'm hoping not to have to sleep with it running very often! So "breeze management" is pretty high on my list. I've even been looking at those breeze catcher hatch covers that the sailboats use a lot.

Oh, and the ducts are up as high as they'd go, but still only half-way up in the saloon. The diffusers point up and down, so that helps keep the air circulating a little. I've had good luck running a table fan, too.

straycat · Aug 2, 2013

Our awnings are miniatures of those on motorhomes. Made of aluminum and attached to the side walls of the boat. They roll up to just under the overhang of the upper deck and are adjustable. Most often, we open them all the way making them perpendicular to the windows and still allowing us to see out. Friends of ours are considering similar awnings that hand roll and attach to the rails when open. The only negative with ours is the need to roll one up when going forward or scrunching down under them to get past. Not a big negative as far as we are concerned. The frame is aluminum and the canvas is attached by running a hemmed edge through a channel. We reconditioned them an in time I will replace the fabric..an easy job.

Did you make screens that attach on the outside of the boat over the windows?
Our windows though old, do not leak, but I hate the inability to clean the exterior of the windows that have screens....considering removing the screens and adding them outside.

Thanks again for your information.! Donna

straycat · Aug 2, 2013

Sortie, where did you have your door made? It looks great! I want to send a photo of our swings for anyone who is interested. Donna

CaptTom · Aug 2, 2013

straycat said:
Did you make screens that attach on the outside of the boat over the windows?
Our windows though old, do not leak, but I hate the inability to clean the exterior of the windows that have screens....considering removing the screens and adding them outside.

We haven't made anything yet, still working through some other projects. The plan is to make panels that snap to the outside of the doors and windows. First will be sunbrella for shade and privacy. Then, for the windows, a screen panel for each opening window with sunbrella (scraps from the first project) hems around the outside to hold the snaps. Finally, I'm thinking a half-and-half panel that's sunbrella over the non-opening window and white mesh over the opening window.

One of the best investments I ever made was a commercial-grade snap tool.

Rick. · Aug 3, 2013

CaptTom,

I have a Prairie 36 which I plan to add ac to in the off season. Where did you end up putting the units and what size?

Apologies for hijacking the thread!!

Thanks,
Rick

CaptTom · Aug 3, 2013

Rick, Welcome! It's great to hear from another Prairie 36 owner!

The boat once had a split system with two compressors and three expansion units that I'm sure worked great, but the guts had been ripped out by a PO, leaving only the registers, thermostats and lots of wire and hose. One expansion unit was over the fridge, and one in each berth.

I ended up going with two 15,000 BTU Dometic systems. One went under the v-berth where one of the old expansion units was, and I used the same intake grill and one 4" duct to a diffuser over the stb side berth. I put a Y on the 6" outlet of the Dometic and ran a new 4" line to a diffuser just to the left of the steering wheel in the saloon. All this was accessible from the stowage area forward of the lower helm station.

The second unit went in the bottom of the stowage area at the bottom of the steps down to the aft cabin. From there it wasn't too hard to run one duct up to the saloon, to the right as you enter the port doorway, and another on the port side of the aft cabin.

None of these are ideal locations, but it's what I could do with what I had. It takes both units to keep the saloon cool on a really hot day, but then the berths get too cool. I hope that getting some shading on the windows and doors helps that in the future. A fan to mix things up helps a lot too.

The two seawater pumps went along the little shelf that the stbd fuel tanks sit on. The breaker panel was already wired for two compressors and I even go to re-use a couple of the wire runs, as well as the two through-hulls for the discharge water. Right now both systems drain to the bilge but I'm working on upgrading to shower sumps for the two showers, so these will eventually go there.

I looked around at other Prairie 36's on the market late last year and early this year. Did you just buy it?

Rick. · Aug 3, 2013

Thanks, I'm glad to have found this forum. We've had her since 1998. I belonged to various other Prairie/Atlantic forums over the years which have all seemed to fizzle out. I've done many many repairs/upgrades over the years, so hopefully I can add something useful to the community.

The PO (original) didn't order her with AC so I'll have to start from scratch. The electrical panel does have the 2nd service for AC but I haven't yet traced out the cable runs, etc. I'm going with marine units and your placement is similar to what I had in mind. I'm thinking a 16k unit for the salon/forward cabin with the unit in the closet forward of the helm. The return will be in the companion way and a vent on the helm "shelf" and one on the closet wall facing forward. The aft cabin unit (probably 12k) will go in one of the two lockers on the port.

I hope to do most of the work myself except for drilling the holes in the bottom, I'll let my fiberglass guy do that!!

Cheers,
Rick

KneeDeep · Sep 9, 2020

Bumping an old thread for more information on your 36 Prairie A/C installations locations.

We have to replace both the original units on our sister ship 37 Atlantic and we don't have many options for placement and ducting using the newer all in one units. (The current current split compressor / air handler system has a terrible configuration too.. as both supplies and returns are within inches of each other :facepalm:

)

CaptTom - If I follow your previous comment, did you use the bottom of the closet on the port side of stair access to the aft bedroom? Our closet has has a lower shelf built in over the engine exhaust run so I don't know if a unit would fit. Would you have any pics of your install?

Our layout is galley down so we don't have any built in cabinetry in the saloon and the forward head is in front of the lower helm.

Rick - anything to share on how and where your install completed?

Thanks for the help!

CaptTom · Sep 9, 2020

KneeDeep said:
CaptTom - If I follow your previous comment, did you use the bottom of the closet on the port side of stair access to the aft bedroom? Our closet has has a lower shelf built in over the engine exhaust run so I don't know if a unit would fit. Would you have any pics of your install?

Yes, that's where I put one unit. I don't recall if it was inboard of the exhaust hose or above it. I added a shelf above the AC, which is easily removable to give access to it. This location allowed me to run short ducts to both the aft cabin and the saloon.

Right now my problem is the long run for the cooling water from the thru-hull in the engine room. I added a new thru-hull for the outflow, but the long inflow hose still restricts it more than I'd like. It's fine in New England, but I think I'll want the full flow when I get to warmer climes. Much as I hate drilling yet another hole in my hull, that's on the list of winter projects.

BobStanski · Sep 17, 2022

Stray Cat

Proud new owners of the Stay Cat #51

Comodave · Sep 17, 2022

Congrats on your new boat. Maybe start a new thread with some photos?

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