For boat owners in the northern regions of the US, winterization is likely the single most important maintenance duty you’ll perform all year. So, as the season begins to draw to a close, you need to be prepared in order to ensure that your boat is suitably prepared for hibernation. 
Winter weather can wreak havoc on a vessel that’s not properly winterized — to the tune of thousands of dollars in repairs and replacement costs. But, on the other hand, when it’s done correctly, little work is needed to make your boat ready for use in the spring. Not to mention that proper winterization can extend the life of your boat and its engine(s) by protecting the components from freezing, corrosion and lying idle for months at a time.
What’s more, freeze damage is usually considered “lack of maintenance” and often falls outside the protection of warranties and boat insurance policies. So, your safest course of action is to call a qualified marine service company and let them perform a comprehensive winterization. 
Even with a shop doing the heavy lifting when it comes to your winterization, there are still some things that you and your family can do to protect your investment and get a jump on next boating season:
- Make sure your holding tanks are empty and fuel tanks are ¾-full before winterization is performed.
- Check and tighten any screws that have loosened during the boating season.
- Make sure drains are clear of debris and flowing freely before closing up the boat for the winter.
- Use a fiberglass cleaner to remove rust stains and other blemishes from your hull and deck now, so they don’t set over the long winter months.
- Add 2 tablespoons of rubbing alcohol to your favorite window cleaner and treat windows to prevent ice from forming over the winter.
- Remove all perishable and freezable items (food, beverages, etc.) from your boat before storage, so they won’t spoil, burst or attract pests.
- Remove any valuable items, including portable electronics.
- Open all lockers, drawers and compartments and clean thoroughly.
- Open and clean the refrigerator and freezer.
- Turn your cushions on edge to allow air to circulate around them, or take them home and clean and store them in a climate-controlled space.
- Remove your lines, fenders and other mooring gear and inspect them for wear and tear. Replace as necessary.
Thanks for sharing such a nice article.There are really a shortage of good article like this.
Does your fuel advice apply to diesel fuel as well?
NO – with diesel fuel, top off fuel tanks and add Biocide. Do not drain fuel lines or run engine out of fuel. Fog the intake on diesel engines.
please check all the gear PFD’s flares and rings.
where do you get the old fashioned lead gas? airports? I know the marinas say they sell gas without ethanol and has special marine additives….cost about $5 per gallon where we get it
WHAT CANDIDATE WILL REPEAL THE REQUIREMENT THAT ETHANOL BE USED IN FUEL?
THIS WOULD SAVE ENERGY, SAVE ALL THE FUEL WHICH MUST BE THROWN OUT, AND THE COST OF REPAIRS BECAUSE OF GOOKED UP CARBURATORS IN OUR GARDEN & MARINE EQUIPMENT. I WILL VOTE ROR HIM WHATEVER HIS PARTY!
Is 3/4 full sufficient for the northwest or completely full?
With this lousy ethaenol fuel we, in my area are forced to buy, you are better off with your tanks empty. Also run all the fuel out of the carbs too. Once that swill seperates you will have a tank full useless paint thinner.
Liked the advise for rubbing alcohol for the windows. Thanks.
So that there is less room in the tank to take on moisture and always use marine grade gas stabilizer,one that fights 10% percent ethanol. My guess
3/4 and not full. Gas starts
turning bad after about 30 days, despite the gas treatment you can add 1/4 new gas.
Use your fogging oil…..
There is ” no winterization for my boat”, I use my boat until the area lakes freeze up, then it is stored with Yamalube in the gas tank for 45-60 days- until ice -out , then it’s back on the water, we are NOT fair weather or weekend fishermen.
Better than adding stabil or seafoam is to just fill up with old fashioned LEAD gas. In my area I can even get hightest. But yeah the closer to full the better you should be.
I use my boat until the area lakes freeze up and then wait two months and then I am back on the water. NOT a weekend or fair weather fisherman
Why? 3/4 quarters full of fuel
so water doesn’t condensate in the fuel tanks.
Less room for condensation to form, so less water in the gas. I prefer close to full.