"What is available is the one piece push around portable air conditioners with the "dryer vent hose" for exhausting hot air
overboard. They are big, clumsy and a royal pain in the butt to try to adapt to a
boat. "
When we got tired of fighting with our
marine unit, this is what we picked up. It does require a place to sit near an opening window, which luckily we have.
As far as efficiency, there are twin hose units that use outside air to cool the coils. Next unit will have this but the cheaper
single hose unit does a decent job. It mixes the
condensation with the
exhaust air so no more plugged up
condensation drains flooding the
bilge (our bilges are dry and it's amazing how much condensation
water an air conditioner will generate.)
So happy not to have to deal with the
marine unit.
As far as powering it we have a Yamaha 2400, which has a built in surge capability and starts our
current and prior units (both 12k btu). At
anchor, we place it on the back
deck outside the
cockpit with the
exhaust facing
overboard. We also have a CO detector in the
cabin.
We thought about the
propane conversion but if you are going to use it on more than very rare occasions, it's just a pain. 95% of
marinas have gas pumps, so it's easy to refill a 5 gal jug.
Propane typically means lugging a heavy tank into town and an even heavier full tank back to the
boat.