The Adventures of the
Sterling Lady
and crew
How to add 10,000 btu of air conditioning to your boat for under $500
Take a good look at the space , empty space available above the forward starboard window, on the bridge , enormous! the window shaker ac Unit will mount inside bridge where the yellow arrow points.
This is the space above the helm. Perfect for intake and a/c out vents. The unit will be mounted "in: the bridge area, in the storage lockers at  the UPPER helm, totally hidden, quieter, and out of sight!!!
Luckily, this area has a false ceiling made of wood, which will allow for cleaner duct work and venting.
Removing the wood, 8 screws, revieled the wiring and original ceiling.
Bought a standard 10,000 btu window air conditoiner from Home Depo, $270. Comes with remote control, which they all seem to have now.
Looking into the UPPER  Helm on the bridge, thru the two doors (now open) the deck has a slant from center to port and starboard.
We built a box to hold the ac unit in place, and measured and cut to make it level.
The smaller square forward is where the intake air will come in.
Note how we notched the aft square to allow all cables and wires underneath to pass  through easily.
The mounting Box , now upside down, was epoxied with west systems. Great way to increase streangth, and prevent rot.
West System cost more, but works EVERYTIME!
Time to place the a/c unit on the mount, and built the air return , and secure the unit. The filter will be place behind the intake grill in the main salon, easy to get at.
The air return box is built (1.) ,and the ac unit is secured in place using blocks of wood (2.) This is done so the unit can be taken out easily if necessary.
From this aft view of the unit, you can see how we had to cut the base to allow for the tilt in the bridge floor, so the unit wold be level. Well , as level as you can be on a boat.
The nearly finished and fitted frame, with vent, is removed from the A/C and again coated with West Systems Resin.
This is how the COLD air will get from the unit, thru a 6 inch flexible insulated a/c duct, into the cabin.
Decided to go with one 6 inch duct, which is enough area to carry efficiently the cold ac.
The metal duct did not quite cover the cold air, so we 5200'd in a piece of epoxied plywood to fill the gap.
Here you an see the 5200 bed we put down between the metal and the plastic to seal the duct.
The air duct is secured to the AC unit, using 5200, screws, and metal tape. Air tight.
The unit is ready to be placed on the mount.
Ready to be mounted. Note the power cord coming out the side, all joints are sealed with either epoxy, 5200, or AC foam or expading foam.
A hold is cut for the cold air vent.
Keep in mind , nearly ever part is store bought, but, they all usually have to be customized or modified to work.
We had to build this wooden mount for the vent adapter to connect to the 6 inch ac duct vent .
Cold air duct hole (blue    ) return air duct hole (red     )
The ac mounting box is screwed in place. Expanding foam is carfully used to clog all unwanted openings.
The return air (red) and cooling air (blue) holes from the inside, looking up.
We attachted the duct work to the ac unit, using screws and  plastic ties. We are ready to put the unit in place.
IT took 3 guys to safely get the AC unit on the aft deck, and two to put it in place on the bridge.
We connected the duct work. First thing we did, plug her in!

Damn if it din't work!
Cooled down the cabin quickly, couldn barley hear ac unit running.
Here is the unit in place , doors open. While cruising, and when the unit is off, the doors will remain closed.
Excuse the mess we are still under construction.
still to come, 110 volts to the bridge for the ac, and finishing the return air duck and filter. today we bought 12 foot of number 10 tinned wire, a plug box and a plug. $30!

There is still a lot to do to finish this job, and I will keep you posted on it's progress.
Here is pretty much the finished product.
The ac is in, the 4 by 8 vent on the left is cold air, the 12 inch square vent with filter is the return.
The Wiring for the 110 volt to the ac will get done soon.
Wireing is run, just has to be hooked up.

Here is the unit, in place mounted under the bridge , and  operatioinal.
The Flexible duct going thru the deck to the vent (1) and the return air duct (2)

Total cost of all parts bought and made, with AC , and mistakes, less than $500.

Cost of a same size marine air, about $1500 plus.
Makes total sence to me. When this unit breaks, and I have leaned from experience , they seem to last about 5 years, I will buy a new one for $300.  A no brainer.

IF you have any questions or comment, feel free to email or call.
This is my fool proof manatee and  $20 burglar alarm.
Curtis the dog bars as all strangers, and at manatees, giving me time to get the gun out, for the burglers of course.
While doing dinner at Sharkeys on $5 hamburger nite, the original African Queen came by on a tour. Well, it's not all original, everything but the outboard hidden under a brown tarp in the back is though.
And on a different note........
hidden outboard
As for the water drain, this unit came with a plug to fit a hose in the round drain hole on the unit.
I drain it, when running , on the open bridge deck.

The new units do not produce much water.


I didn't insulate the metal connector from the air duct ,( at The YELLOW ARROW) to the vent in the wall. This caused condensation.

The simple fix, bought 1 inch closed foam, (because I hate fiberglass) and  wrapped it around the metal vent with duct tape.
Seems to have worked.