Archives has a lot
Previous owners may have set up boats in a variety of manners. It also depends on where you are wintering-on the hard, in the water, deep south, freezin' north, etc. I suggest you check the archives first, and then post specific questions. I'll tell you now, I went to an RV store and got a hot water bypass setup (two valves and a hose, which you may need a longer hose than the standard). That allows you to just drain the hot water heater and winterize just water lines around it-much better.For the AC, get the pink stuff running in lieu of water and shut her down.