A/C Mod for Mac26X

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OverEasy
Admiral
Posts: 2010
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

A/C Mod for Mac26X

Post by OverEasy »

Hi All

This is our Air Conditioning Mod for a Mac26X.

We took a 6000 BTU 115 VAC portable single exhaust tube room A/C unit and installed it in our Mac26X just aft of the battery box next to the Galley.

We looked at several different options but decided on the simplistic approach at this time.

The addition of 2 eyelets to the aft of the battery box allows for a ratcheting tie down to hold the A/C unit in place. We contemplated mounting it to the starboard side sort of behind the head in the aft berth to better balance the boat (as the dual batteries are in the port side) but the access geometry really didn’t work for us.

The single vent pipe was placed in a cutout and hatch in the starboard cockpit bench wall.
We cut the opening to fit the same style and model as we have used previously for the fuel tanks mod and for the electrical mods. We then modified the hatch to have a two loop pin latch mechanism. A SST strap hinge was located about 1/3 the way down from the hinge on the inner face of the hatch interior wall to act as a prop to keep the hatch open for venting.

Yes a single exhaust tube A/C unit does rob some of the interior air to cool the unit and Yes this does draw in outside air at the hatch openings but with a piece of pipe foam we have been able to nicely control the leakage inwardly with slip pipe insulation tubes.


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One does need to remember to open the vent hatch and prop it open with the strap hinge before turning on the A/C.

Yes this A/C approach limits it’s use to where we can obtain shore power at a marina or at campgrounds but it really has been a very enjoyable modification! It has made our trip much much much more enjoyable!

Best Regards,
Over Easy
😎😎🐩🐰
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Russ
Admiral
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Joined: Thu Oct 11, 2007 12:01 pm
Sailboat: MacGregor 26M
Location: Bozeman, Montana "Luna Azul" 2008 M 70hp Suzi

Re: A/C Mod for Mac26X

Post by Russ »

Very nice mod. Clean and professional looking.

You should post this in the mods section here
https://macgregorsailors.com/mods/
--Russ
OverEasy
Admiral
Posts: 2010
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

Re: A/C Mod for Mac26X

Post by OverEasy »

Hi Russ!

Yup 👍 :) :) ABD 8) 8)
Sheppie62
First Officer
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Sailboat: MacGregor 26X
Location: Mission Bay San Diego

Re: A/C Mod for Mac26X

Post by Sheppie62 »

Nice much better than stepping over it ! If you used a 2 vent unit behind the head, you could have vented the bathroom. :D
OverEasy
Admiral
Posts: 2010
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

Re: A/C Mod for Mac26X

Post by OverEasy »

Hi Sheppie62!

You might be on to something there… 🤔

Vent the head closet to the outside as the intake to the A/C then vent the A/C exhaust overboard…
That would kill two birds with one project…. Hmmm…🤔 ….. gotta think some on that one….
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Jimmyt
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Sailboat: MacGregor 26M
Location: Mobile AL 2013 26M, 60 Etec

Re: A/C Mod for Mac26X

Post by Jimmyt »

Sheppie62 wrote: Sun Oct 17, 2021 10:14 am Nice much better than stepping over it ! If you used a 2 vent unit behind the head, you could have vented the bathroom. :D
Now that's what I call using your head! :D (See what I did there?) :wink:
Jimmyt
P-Cub-Boo
2013 26M, Etec 60, roller Genoa, roller main
Cruising Waters: Mobile Bay, Western Shore, Fowl River
OverEasy
Admiral
Posts: 2010
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

Re: A/C Mod for Mac26X

Post by OverEasy »

:D :D
OverEasy
Admiral
Posts: 2010
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

Re: A/C Mod for Mac26X

Post by OverEasy »

Hi All!

Looking over the trip notes from our recent 70 days on the water on Lake Champlain ( last week of August through September to the end of October) we found that the A/C mod was really appreciated and enjoyed during the hot and humid days.

It did a great job of cooling off the cabin even on the hottest (95 F+) days.
It did a great job of dehumidify too!

When running the regular A/C function the exhausting air was more than capable of evaporating any condensation precluding the need for any collection drainage. This was on many very hot and very humid days.

When just running the dehumidifier option the small built in collection tank was capable of several hours of operation before becoming filled and needing to be drained. Our initial installation really didn’t address this aspect as the expectation had been that we would primarily use just the A/C function.

But as the weather cooled off into the later part of September and into October this was no longer the case. Humidity from cooking (boiling water for pasta, soup, coffee, etc…) as well as respiration’s while sleeping tended to increase the interior cabin humidity. This became more prevalent, especially when we sealed up and turned on the heating. We would often develop condensation on the more exposed surfaces with less boundary material of the cabin ceiling and hull. ☔️ The exposed cooler surfaces of the cabin interior weren’t the only places where condensation occurred. It also occurred in the interspace areas between the cabin inner liner and the exterior hull regions.

Then when running the dehumidifier function it was found that the limited size of the built in tank was a bit of an annoyance having to periodically stop and drain it. While we could have just allowed the condensate drain to flow into the starboard bilge area and let the bilge pump eventually send it overboard we really didn’t like the idea of having that large an area wet all the time. (Personally we don’t like dampness within the boat as it could eventually lead to mold and/or mildew issues even in cold weather.

So during the trip we just ran the dehumidifier as needed and took the time to drain the built in collection tank.

Now that we are back to our home in SC we are making plans to add a “mini bilge & pump” system to allow the A/C unit to drain automatically.

There isn’t access or sufficient room within the A/C unit itself so we are going to make a fiberglass shell collection tank that will fit within the bilge area accessible from one of the aft berth access hatches. Within that tank we will mount a small automatic bilge pump in a recessed area (to further minimize any residual water as most bilge pumps can’t completely empty a tank due to the nature of a centripetal pump.. The small diameter discharge line will then be fed to a high mounted through hull.The tank will be sealed with a screwed on gasketed lid so that the pump can be serviced and/or cleaned if need be. It will also have an interior float switch feeding to a high level indicator light on the control panel as a back stop to the bilge pump.

(Note:As this is just for the dehumidifier collection we’re not concerned with volumetric throughput as much as head lift height for the bilge pump so we might look at using a small diaphragm type pump.)

Another approach we are looking at to achieve the same result is to use a small automotive windshield washer tank/pump arrangement that is turned on via a simple float switch. We could mount something like that in the area under the aft dinette bench seat.

With this we can run the dehumidifier function in all weather conditions without concern or the need to manually empty the accumulation tank AND ensure that there is minimal moisture or condensation anywhere within the interior of the vessel in any temperature conditions.

Best Regards,
Over Easy
😎😎🐩🐈
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rsvpasap
Engineer
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Joined: Fri Dec 13, 2013 2:05 pm
Sailboat: MacGregor 26X
Location: Seattle, WA

Re: A/C Mod for Mac26X

Post by rsvpasap »

The Attwood sump box has worked dependably on my 26X as the shower sump for at least six years. It lives in the bilge just aft of the head (fits perfectly under the floor) and pumps out to a T-fitting in the starboard lav drain line. Something like this might work for your purposes. (Canadian rules may require a holding tank.)

https://www.google.com/search?q=marine ... sump+box

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Starscream
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Location: Montreal, Quebec. 2002 26X - Suzi DF90A

Re: A/C Mod for Mac26X

Post by Starscream »

Looks like a good mod. I've been thinking about A/C, even though we only need it a few days per year. If we do add AC, it will be a window unit for dock-use only, installed in the cockpit, at the front dodger roll-up window, to condition the cockpit enclosure, and by extension, the cabin below. It would be easy to fabricate some sunbrella flaps using the window zippers to isolate the AC into the dodger.


It's a little hard to tell from your photos, but is there an additional tie-down to support the main unit when sailing under "spirited" conditions? I'd be a bit concerned about the unit's stability when heeling 20 to 25 degrees and smacking a wave or two.
OverEasy
Admiral
Posts: 2010
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

Re: A/C Mod for Mac26X

Post by OverEasy »

Hi StarScream!

Thanks!

Yes, there is a ratchet strap band around the lower portion that hooks into the aft wall of the little stoop seat/battery box on our Mac26X. We also have some captured round tube foam compression spacers to help take up the space gaps. We’ve been out in some 2 and 3 foot waves motoring at 6 to 8 mph for extended periods and the A/C has been rock steady. Having the weight low the the boat helps with the center of gravity and stability.

We originally thought about window unit in a ‘Billy Box’ in the companionway but when I mocked it out with a cardboard box we didn’t like having the extra obstacle to climb over/on. It also took up cockpit floor space which is already limited.

We also looked at and evaluated mounting a window unit on or I n place of the forward hatch.
The vent ducting to take the horizontal cold air discharge and redirect it down into the cabin would have taken some additional space and added some complexity. The high mounted weight aspect would have messed with raising the center of gravity. Then there was the exposure of the condenser & evaporator coils to the elements (we are located on ‘salt’ water when in SC. Didn’t seem like a good fit for us.

We also looked into using a rooftop RV A/C unit at the forward hatch location. Better in that it was already in a streamlined smooth surfaces enclosure with bottom cold air discharge ports. But the high mounted weight and unit cost were giving us pause.

Last alternative location we evaluated was on the companionway sliding lid. Both with a window unit and with a RV rooftop unit. The high mounted weight was a concern again and it’s impact of raising the center of gravity. Then the aspect of adding a bulky box as an obstruction to the top deck. Finally there was the cutting into the hatch to mount it didn’t even get much traction.

We don’t have a dodger yet and really couldn’t consider your approach of just resting the window unit on top of the companionway hatch and directing the cold air within the enclosed dodger area. The high mounted weight, deck obstruction or having to dismount/store the A/C unit also gave us pause when considered in light of our objective of eventually cruising the INTRA COASTAL WATERWAY (ICW) and Eastern Coast as well as using or Mac26X as an occasional land camper.

For us the solution was the portable unit mounted in the aft berth area.

While I would have preferred a dual hose unit that type wasn’t available at the time so we went with the single hose type. I’ll be adding an cooling air box and duct this off season so that it doesn’t have to use cabin air to cool the condenser.

Overall, for us and our needs, the low mounted portable was our best option and we don’t regret it. Especially after our extended 70 night on water trip to Lake Champlain. The A/C was really appreciated in the hot weather and the dehumidifier was of benefit in the cooler/cold weather. :) :)

The other thing we may do is move the unit and ducting from the Starboard side to the Port side of the aft berth for better weight distribution given that the dual batteries are also on the Starboard side. We’ll have to look into that further though to evaluate the alternatives such as adding fresh water storage and grey water holding tanks to the Port side which would help balance things out just as well (as long as there is water in them :D :D ).

Part of our modification plans is to make a removable enclosed hard dodger, stern arch solar Bimini and cockpit enclosure. All of these things add up weight and have the potential to shift the center of gravity upwards so we tend to try and think things through the options a couple different ways before doing.

Best Regards,
Over Easy
😎😎🐩🐈
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