I did a little more checking into the power consumption, and 10 HP would be the max with older AC units, while some of the newer ones only suck down about 5 HP when running full blast.
Someone also posted something about the hatch being sealed sufficiently to use AC. Here's some photos of my current hatch setup.
When the boat is buttoned up tight and I'm not there, there's a vent in the hatch, and another in the head door. There's a solar powered exhaust fan in the head that draws air through the boat and keeps things odor free.
When I'm sailing or at anchor, I have some custom made doors that have Lexan panes with nylon screens behind the panes. The panes are removable and allow lots of air to enter the cabin. When I'm at the dock, with the AC running, the panes are in place, thereby providing light, plus easy access to an air conditioned cabin. The doors are easily removed and store beneath one of the seats in the cabin.