You may already know to add the usual anti freeze in the potable water system. But do NOT forget to run the pink fluid through all of your boat’s pipes, even to the aft deck shower and water heater. This will purge out the potable water and replace it with with the proper drinking water anti freeze. BEWARE- Do not use engine antifreeze as this is poison.
When the purging process is complete you must see a pinkish fluid run out of the hot and cold water faucet in each sink, in the head shower and even from the aft deck shower to confirm the system has been filled with anti freeze.
Follow your boat yard recommendations for the engine and generator freeze protection and anything else they may see needing attention. Shrink wrapping the boat is an idea for outdoor storage to prevent leaves from collecting on deck or snow and ice from weighing down the deck.Indoor climatized storage may be available in colder climates or hurricane zones.
A strange thing happened to us in Jacksonville, FL one winter. The temps plummeted down to 17F Brrrrr! We didn’t like it and neither did our hand rail tubing. The handrail must have had some water trapped inside the tubing. The water froze during the night and the pipe burst. When I saw this the next morning I drilled a small hole in the bottom of the tubing to prevent future rain water from collecting and freezing.
Think outside the box. There may be more to freeze protection than you first assumed. Talk to your dock neighbors and collect their thoughts. Experience can be a hard way to learn if your winter is a c-c-cold one!