I store our C26 in heated storage. I wish I was using the boat in Florida but thats another story. If you are storing it and do not plan on working on it or checking on it over the winter Mike is right on. The only thing I would add to it is attach a tag to the key fob and steering wheel stating all sea cocks are closed. When I was a service technician many times I replaced impellers because the marina launching the boat or the owner forgot to check the position of the valves.
The marina that I store the boat allows me to work on the boat over the winter. I spend time working on it frequently. I leave the water tank and hot water tank with water. I actually use the water during the winter and add to it as needed with a portable water container. I have fresh water flush for head, I flush it and run water from the faucets hot and cold to help flush lines. I run the boat in fresh water so far !!! Flushing isn't necessary, but I still flush with tap water when heating the engine for an oil change. Batteries I leave connected and charge when I'm working on the boat. When I'm not there battery switches are off. I pull the fuse for the refrigerator, NEMA 2000 power, radio, and CO detector. these are either powered all the time or not needed over the winter. The fuses are put in a baggie and tie strapped to the steering wheel. Many of the boats in the building the owners do nothing. The last day of boating the owner calls the marina, tells the service department haul the boat. It gets put in the building and the owners walk back on it in the spring in the water.
