Marine A/Cs are more than 'portables', but imho they are vastly superior if you actually NEED A/C. If you are in northern climes they may do, but here in Atlanta they can't cut it when the air temp is near 100... We had tried a cruise-air portable unit and it did not do anything but drip condensate on us. Then we put a Webasto 24,000 110V a/c in. On the hottest day you could hang meat in the cabin, (Cool 20 degrees in 20 min.) but it was over-sized and would overshoot the target temp by 5 degrees due to minimum run times. We switched to a Webasto 16,000 unit last year. It takes about 3 hours to cool 20 degrees (92 to 72) but once there it can keep it all day/night if you keep the hatches closed.
I installed it myself. I moved the batteries from under the nav station and cut the bottom out of the battery tray. Ran ducts forward to hanging locker and v-berth, and another up and forward to middle of starboard shelf. Had to drill a few 4" holes and one 2"x 6" ellipse for the duct work. Built a platform and installed A/C under Nav Station. Since we can not discharge black water, I used the macerator thru-hull for the raw water intake. See my
Pintrest page for more.