air conditioning

[CruzinBluezn]

Dealing with South Georgia's high humidity and temperatures encouraged this sea water air conditioning mod. The 26x early 1996 models had an additional ballast tank pick-up at the approx. center bottom of the boat. I have been using one of the 1" holes provided by Mac to attach the a/c pump suction line. A 316 stainless screen was sealed over the existing hull recess. This acts as the raw seawater filter. The main issue to overcome is part of the suction line(about 6 inches) is above the water line which is a no no on any of the Manufactures instructions when installing this type of system. ( the high spot occurs on my boat where the suction line exits the cabin step to go on to the water pump. I dealt with this by using a check valve in the suction line ( which is also frowned on by the manufactures). The risk here is if the suction line check valve fails the centrifugal water pump (which doesn't "pull" water) won't be primed on the next start up hence risking overheating the water pump seals. After 5 years of use and once a year inspections this has not been a problem. The concept of using a check valve is exactly the same as how a lawn sprinkler system operates. Lawn systems with a well also use a centrifugal water pump and a check valve in the suction line to keep the pump primed when shut off in between lawn watering days.
The 5000BTU unit is installed under the galley. A/C maintains cabin temp about 15 degrees lower than outside temp and removes much of the humidity from interior for better sleeping.

[NiceAft]

Is this used only at a dock where there is a power source? If not, how long can you run it on battery power?

Ray

[CruzinBluezn]

Ray;
Typically I'll use when sleeping at a marina. However, the Honda EU2000 will power the a/c at anchor. I've used it this way several times when I wanted to be more comfortable. Don't really mind the humidity when alone and will use a good DC fan a lot when anchored, but with someone else aboard It can get pretty sticky in the evenings during the summer months. Possibly the smaller EU1000 would work also. After a lot of researching I realized battery power is not feasible to run a decent sized air conditioner and I didn't want to go the route of a window unit. Any decent air conditioning that actually works appears to be limited to ac power. This unit, Mermaids smallest, is hidden under the galley so doesn't take up walking/headroom in the cabin. It was also nice when I first installed it to have that stream of discharge air conditioning water coming out the thru hull fitting like the bigger boats. Keith

[Russ]

Nice. Anyway to avoid putting another hole in the bottom is good.
Seems much better than stepping over a window unit in the companionway.

I still don't understand the "extra" ballast hole on the early X, but it looks like you made it work.

[CruzinBluezn]

I posted a few pictures in the MOD section Russ that might help explain. When I bought the boat used the Mac 26X brochure the boat dealer gave me didn't even show it. I'm thinking they only ran it that way maybe for half the year in 1996 if that.

[Russ]

Nice mod.

I really like the installed ac systems. Water cooled also is more efficient and quiet. This is how I would do it. I assume you have a carbon monoxide detector when running the genset.
Why didn't you go with a larger unit. Seems only adds one more inch



--Russ

[CruzinBluezn]

I always keep fresh batteries in the carb detector and smoke detector. Don't recall why I went with the smallest unit except I wanted some room to make a closeout with sliding doors to keep small items like coffee cups. Yes its very quiet. With the closeout in place less noise than a box fan in the cabin for sure.

[kurz]

Sorry, but how does the watercoled air con work? No compressor system? Thanks.

[Russ]

Sorry, but how does the watercoled air con work? No compressor system? Thanks.

Water cooled uses a compressor, however instead of a air cooled condenser like a home air conditioner, it is cooled by pumping water through a heat exchanger. This makes it much more efficient. The back of a window unit has cooling fins that use a fan to exchange the heat taken from the air inside. A central AC unit has the condenser outside by the compressor. As ambient air temps rise (typically when you want air conditioning the most) this becomes less efficient as the condenser is being cooled with hotter air.

A water cooled unit allows it to be mounted entirely inside the cabin without the need for air venting outside. When you walk into a marina and see a stream of water pouring out of boats, that's probably their AC water pumps.

Sea water makes for a much better coolant. However, it also introduces more issues, such as fouling from sea life. I have a friend who had his AC unit clogged with jelly fish. Was a mess to clean out. That where the screen in this install comes into play.

[Russ]

Very nice install. Should be worth noting how you double clamped hoses that are below the waterline with quality SS clamps. Very smart. A clamp failure could cause a serious problem there.

[RobertB]

I finally tried out my AC installation this past weekend. As I was not yet ready to install a full up marine water cooled system, I opted for a free standing dual hose system. The Admiral was very pleased and even had to ask me for another blanket.

I am still considering the marine unit. I would most likely install further forward to address my stern heavy situation. Big issue I need to resolve is the opinion of others that have the system in boats on the Chesapeake Bay that the cooling water loop is easily clogged.
If I install under the v-berth starboard side, I was considering the return at floor level far forward and supply vents at the same level amidships. Not ideal but the boat really is not set up for central AC ducting.

[Catigale]

We suffer from having to travel south to sail in winter, but the cool New England summers without AC are to die for....especially for those of us polar bears that God never intended to live below 43 degrees latitude.

[wbpenney]

I installed a 9000 btu Mermaid reverse cycle unit in my 2008 M. I have since upgraded to a 12000 btu unit (considering extending AC to enclosed cockpit area). The 9000 btu installed can be seen on http://boomboom2.blogspot.com/. I will load the pics of the 12000 upgrade ASAP. The only modifications I had to do was lower the mounts, larger air outlet at head area ( 4 x 10) and changed the 4" ducting to 6" to under the head.

[kurz]

this looks for me quite interesting:
https://notvorsorge.com/camping/split-k ... e-ac-2400/

[Russ]

Kurz, I wouldn't think you need air conditioning in Switzerland. We don't need air conditioning at all here. Open windows work great at night.

That's an interesting unit. I guess the advantage is it folds up. I'm not sure how to mount it on the Mac.