What is the process for boats becoming "winterized"? Do all boats need to become winterized and is this a one-time process?

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    @Liam Winterizing a boat is not that different then winterizing a camper/RV/Trailer or a vacation home. In all cases it pretty much 2 fold, 1. deal with any fluids that may freeze and expand (fresh water, etc). 2. Protect object from weather hazards. Commented Mar 17, 2016 at 13:40
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    @Tom, This question might be too broad, A row boat at a river dock, a sailboat on a fresh water lake, and cabin cruiser on saltwater are all going to have different requirements, and if the body of water tends to freeze will impact the answer. Commented Mar 17, 2016 at 13:42
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    This can come with a very general answer or a very long detailed one for each situation, would it be possible to narrow it down? Commented Mar 17, 2016 at 14:27
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    @JamesJenkins, im not sure the even the OP is understanding what winterizing means since he asks if its an one time process Commented Mar 17, 2016 at 14:28
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    It is clear that no one who has commented is a boater or sailor and has never taken the USPS safety class. Please do so before taking to the water. Lives and expensive property is at stake.
    – SkipBerne
    Commented Mar 17, 2016 at 15:03

1 Answer 1


Winterizing a boat. The issues are 2 fold at a minimum. 1 freeze protection. 2 element protection.

  1. Freeze protection - two basic areas engine and water tanks. Water tanks hoses, and fixtures can be protected two ways, evacuation of all water or mixing the existing water with polypropylene glycol or vodka. ONLY. It is EPA FDA safe...anything else is poisonous. Clear the bilge of water with a wet/dry shop vac. or add vodka.
    Engine. Clear water cooling apparatus from stem to stern of water or mix with polypropylene glycol or vodka only. Remove all water pump covers and let lines air breath if possible Automotive ethylene and di ethylene glycol is ILLEGAL. Antifreeze is ILLEGAL as it will be pushed into the water on startup in the spring and subjecting the operator AND owner to a $500,000.00US fine. Clearing water from fuel/water separators and adding fuel stabilizers is recommended. Change the oil in the spring. Using an unattended heater is NOT recommended to keep components from freezing. FIRES are very common with this approach.

  2. Element protection - depends on if you are hauling out the boat or leaving it at dock in the water. If hauling out then protecting the decks and scuppers from ice and snow fall as well as freezing drains in the cockpit or like areas is important. Some shrinkwrap the entire boat. A waste of money and material. if you keep the boat in the water you have to check on the boat periodically, and if there is potential for freezing a hull heater or an air bubbler or ice prop, to keep the ice from forming at the waterline and crushing the hull is necessary.

Removing things like sails and lines is a good idea to protect from ice and freeze shredding. Do not use home depot tarps as the wind will shred them.

  • You mention a couple of substances as illegal, but it should be safe to assume that's country-specific. Could you clarify in which country/countries you know them to be illegal?
    – Roflo
    Commented Mar 17, 2016 at 17:03
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    If you safely and responsibly operate a marine vessel you would know what the fines for intentional and negligent water pollution are in your jurisdiction.
    – SkipBerne
    Commented Mar 18, 2016 at 12:43

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