Generally, anything that uses water for cooling or carries water for use on board, needs to be winterized. Fall is also the perfect time to do your annual oil change and transmission fluid, or lower-unit gear-lube change on your engines. Make sure your to-do list includes: Oil change and cylinder fogging for engines and generators.
- Lower-unit gear-lube change for outboards or sterndrives.
- Topping off the fuel tank, adding stabilizer or biocides as needed.
- Draining or flushing/filling any raw-water cooling systems with nontoxic antifreeze. Don't forget the air-conditioning system.
- Water system winterization, which can be draining or flushing or filling, depending on your preference. This includes tanks, heads, pumps, shower sumps, sinks, and even seacocks, if the hose runs don't drain entirely.
- Inspection of anodes and running gear.
- Washing the exterior of the boat to remove salt and dirt, and getting the cockpit or other exterior drains cleared.
- Make sure batteries are fully charged, or better yet, remove them where they can be stored indoors and given a booster charge from time to time to keep them topped up.