What are the nuts and bolts and sequence of operation of an A/C unit aboard a pleasure boat, say 50-60 footer?

I am referring to an older boat that still might be charged with R22. It is probably using a water cooled condenser (heat exchange) and I am guessing that that is the most troublesome component part of the system and if it is leaking through, can it be repaired or is it best to replace it? In the past I have worked on marine type refrigeration all of it air cooled and often one condensing unit supplying several medium temp cabinets and maybe a low temp as well. This was way back in the 60's at the Hampton Bays Long Island Basin