I will be in need of AC in my Catalina27 soon. I already have at least 6 thru hull fittings and don't really want any more holes in my boat to accommodate the built in units, so what about the carryons? I'm leaning toward the Cruisair 5000, if I can find one, or a small btu portable to keep inside the boat. Any suggestions or ideas where I can find a used unit. I plan to install a 3 battery dedicated bank to run it for a few hours while we are out on the water. One company actually sells a little 1000btu unit that only uses 250 watts, but will that really cool a C27?