I would also think using seawater to cool the condenser would markedly up the ac systems efficiency! And the size could be greatly reduced.
Come on u badazzes use your melons there are some smart mofos on the board that im sure can add some other good ideas... rm

Never seen a ac unit with a SEER rating of 35(looking at your second link) but if its true then you may really have something!

Lets just say the solar panels can power the a/c unit, what are the specs on it's ability to cool? What will it cool 85* or higher ambient air temp in the cabana down to?

Biggest issue I see is that the main time I would want A/C is at night when we are sleeping in the boat. Will there be a option to plug into shore power to run at night?

I work in the hvac field, to say I'm an expert is probably a long shot. I do have some knowledge on the the theory in question. First, inverter technology is the way the market is going. It is more efficient and doesn't take a big power surge to start it. You convert an ac signal to dc, then smooth it out and back to ac. It gives you a false ac but the compressor doesn't know any better. They also take single phase and convert it into 3 phase while doing this. This allows them to spin the compressor, especially for heat, up to 300x faster then running at 60 hertz. The other luxury is no high starting amps. Think of it like a VFD or a motor starter for a larger 50hp electric motor. Noone just flips a switch and starts them, you just slowly increase the heartz/ volts and it starts nice and smoothly.

As to the never seeing an a/c system with a seer of 35. Mitsubishi and Fujitsu have 9,000 btu air to air mini split systems that have a seer of 30. If you can use the water and have a more controlled head pressure the possibility of a 35 seer is there. I can't say the solar panels would work well for the boat, however of you already have shore power or a gen. I w I would think that an inverter water source mini split would be the ticket on a boat. You could get heat or cool very easily and then use very little power to operate it. I think you are on the right track island, just make it run on either the solar or the power in the boat.

What I think you should do is find a way to get the existing type of self-contained water-cooled units to run on dc-inverter technology. Then develop a new swim platform where the whole surface of the platform is a solar panel. A couple of extra batteries and a solar charger / inverter. During the day A/c runs off of solar, at night if batteries run out switch to shorepower or if not available by then you're probably sleeping anyway.
My 2 sense !

On the subject of your hotel, I have these beautiful, ultra-quiet room units that are perfect for hotel rooms. They are completely self-contained and do not require the outdoor condensing unit. I've been testing them for about 2 years and they work great. How many do you need ?

Ive never seen them water cooled, can you send me a link to check them out? Thx, rm

I don't believe there is one. That's why I was saying. If you can put an inverter mini split and combine it with a water source heat pump you would have the best system for a boat. All you should really need to do is make the outside could a water cooled coil and there you go. Figure your temp will go from 55 to 85 on your water temp as apposed to 0 to 100. ( those are temps in pittsburgh)