In one short post I can't tell your experience level, so excuse me if I am being too elementary. But since you are looking for a manual for your
boat, let me say this.
Unlike cars, boat manufacturers don't make their own
equipment. All the
equipment comes from different places. And, unless your boat is practically brand new, some or most of that equipment may have been replaced. On top of that, most boat owners
manuals are actually some
documentation on specifics to that boat, along with a pouch of individual
manuals from the people that made the different equipment in that boat.
So, long story short, I think what you really want to look for is the manual for the A/C system that is in your boat. You'll have a much easier time finding that. If you can't find it through a
Google search, post the make and model in here and maybe someone can help.
-dan