If its less than 3 or 4 cabins that you need to air condition, a self-contained sea water cooled unit such as the Webasto Blue Cool series would be best.
If there are more than 4 cabins, a chilled water system would be recommended.
The residential type split systems are cheaper, but they do not last long and the manufacturers will not warrant them in a marine application.

Use the following chart to work out the required size. View here

At least once a year. The sea water condensers do foul up causing high pressure faults.

Failure to clean the sea water strainers reduces the efficiency of the units and eventually leads to the equipment cutting out on a fault.

Eutectic refrigeration system freezes a glycol solution which acts as a thermal storage cell. When power is available the compressor runs and freezes the glycol. Then when there is no power available the glycol slowly thaws whilst maintaining the cool box temperature.

Webasto have a range of diesel fuelled hot water systems which can be utilised.