Prairie 36_Atlantic 37 A/C Configuration

We are looking at a project to upgrade our A/C systems and I am curious of the location and venting setup on similar vessels out there.

Currently have Cruise Air split systems with 2 compressors in the engine rooms and 3 air handlers.

Our salon unit is in the wall along the floor on the port side with the return, vent and thermostat all within the same few feet so our circulation is poor. The forward cabin unit is under the bunk but the return air setup is not sealed well and it is slaved off the unit in our bedroom cabin which is also in the wall on the floor with the vent and thermostat just above the return air. Needless to say we short cycle a bit and the systems are probably not very efficient.

I noticed on the pictures that Cruiser just posted on the classified for his Prairie 36 (great looking boat by the way) that his a/c controls and vents are in the back of the bedroom cabin, and I have seen other pics of different cabin set ups.

I would like to convert over to the new self contained units, but don't really want to keep them in their current locations so we are looking for options.

Mine originally had the same split system as yours, but everything in the engine room had been removed. I ripped out the rest and went with two, 15,000 BTU self-contained units.

One is under the V berth, starboard side, with one duct going to the original vent over the berth, and another discharging into the saloon just behind the wheel at the helm. I have the full "V", not the "bunk" arrangement forward. The intake uses the existing intake grill.

The other is at the bottom of the stowage compartment on the port side of the steps leading to the aft cabin. The intake is through a new grill near the sole. One vent blows out into the cabin from the port, another blows out into the saloon below the small shelf at the top of the steps.

Placement of the thermostats is important. I thought I'd found good locations, but one of them always reads high, as if it's in a "dead spot" where air doesn't circulate.

The space over the fridge in the galley where there used to be an evaporator in the split system became a great new stowage cabinet.

I can run either unit on a 15A power connection without blowing fuses, which helps when traveling. I've probably used the reverse-cycle heat as much as the AC.

Overall, this arrangement seems adequate for "normal" use here in the Northeast.

I don't know if running both units would keep the boat cool all day in the hot Florida sun, but on those hot (90-100 F) and humid days here it at least keeps the air a lot dryer and a noticably cooler inside.

The only things I'd change would be to add a cooling water discharge closer to the aft unit (it runs all the way forward, now) and relocate one thermostat. If cruising warmer climates I might consider a third, smaller unit under the seating in the saloon. This boat absorbs a lot of heat from the sun.

I have 2 self contained units on my Prairie 36. One unit is located under the settee in the salon with the return in the same cabinet. There are 3 vents; one in the V berth coming out of the bulkhead just below the port side portlight, one in the salon coming out the top of the cabinet just aft of the port side door, and the last in the aft stateroom coming out just aft of the hanging closet door. The other unit is located in the cabinet above the refrigerator with the return in the forward cabinet doors and a vent on each side of the cabinet.

I've only used the units a couple of times here in Southeastern North Carolina and they do cool down the boat nicely. I agree with Tom that the boat absorbs a lot of heat from the sun.

KneeDeep said:

Do you have the head/shower in front of the lower helm? If so, where do you run the vent from the under the v-berth to the helm?

I think 2 15k units will be the way to go - if i can figure out where they will fit with limited carpentry changes.

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My forward head is to port. In front of that is the full V berth. Opposite the head, forward of the lower helm, is a stowage cabinet and access to the helm controls. The vent runs through there and discharges through the bulkhead into the saloon.

If you've got the head on the starboard side, then it should be easy enough to run a duct through the bulkhead into the saloon, and discharge under the seating.

The 15K units I bought are now sold with a 16K rating, which is more common. I was told they're essentially the same, it was just the way they rated them at the time. (I bought the prior years' model at Defender's warehouse sale.) Either way, two of those seem to be about the best arrangement.

I've toyed with the idea of adding a third, 9K unit just for the saloon. That would add extra capacity for a quicker cool-down on those really hot, sunny days. Also the ability to run just the smaller unit on those days when you only want to take the chill off or dehumidify the air a little. So far that idea has never even made it onto the wish list.