inverters and air conditioners
There are two DC air cooling units that I know of. One, Cool Currents, works by pumping water from under the boat through a radiator and has a fan to blow the air across. This would not work well in FLA or the islands where the water is warm.
There is another unit I just saw in the West Marine catalog. It uses ICE in a regular ice chest to cool the fluid going through the system. On paper, this actually looks like it could work well. Might be difficult to regulate the temperature of the cool air, as the ice melts... but it looks like the only real solution that has a chance of working.
I do agree with the fan though. I like fans much better than AC.
Hope this helps.