RE: Need marine air-conditioning book
The big hassle might be AGE , as the older units used the more efficient F-12 , the new units a crappy substitute .
F -12 is no longer here in the US (getting harder to find in Mexico or the Bahamas) and "converting" to a newer refrigerant is a waste of time , even if you can do it at home.
Since many units are 20 -30 years old , its time for a new set of units.
The only other ( Po Boy) alternative is a mixture of 90% propane and 10% butane , which is even better refrigerant than the old F-12 ,(same oil, TX valve and settings) but the dangers of an explosive gas in the bilge make it a choice ONLY for boats with propane cooking and gas detection system on board.