I have often found it better to go to Google, and use "xxxxx" site:c-brats.com .
For example "air conditioning site:c-brats.com".
All of the first articles are gong to be about C Dory and air conditioning.
For example one which would be good for you on the
Tom Cat will give you a lot of information on different ways to do the ac on the Tom Cat. Included in this is a mention of basically a tutorial I did when putting the Polar Cub on my Tom Cat 255, including making a wooden frame on the inside of the cabin, the same as the contour of the roof, and making a flat "platform" for the mount on the external for the RV air conditioner unit.
For many of us the RV air conditioner (or a window air conditioner) make the best sense. This way, you can air condition the boat, when on the trailer, when on a lift, when in shoal water, when there are lots of jelly fish, or masses of kelp which will plug up a strainer, etc...
I found out on this trip, when Mark loaned me his window unit --(we hadn't counted on the heat in Missouri) which didn't fit the 22's window, but worked very well when placed in the cabin door, with the curtain over the upper part, and a fan to blow the cold air forward... Mark has a built in marine air conditioner for times on the water, but when "boater home" camping, the marine will not work, and the window makes a great substitute.
Also the subject of generators comes up--and many of us use the EU 1000 or EU 2000 to run the air conditioners. One can go up in size, if you use the expensive Dominic
Smart Start.