To Winterize or Not Winterize…

For boaters up north, there’s not much choice. Sometime not long after the first Green Bay Packers game is played each year, your boat goes into hibernation for the excruciatingly long winter. If you live up nort’, you know the drill: Give the boat a final cleaning, take everything out, fog the engine, remove the batteries, drain and run pink antifreeze through all the water systems, create a PVC-pipe skeleton inside the boat and cocoon your baby in shrinkwrap until the spring metamorphosis. But what about boaters south of the Mason Dixon Line? Is there a way to keep boats safe and still be able to take advantage of the occasional warm spell? Yes. But one word of caution: According to BoatU.S. insurance statistics, the state with the most reported cases of freeze-related boat damage isn’t Wisconsin or Minnesota. It’s California. Huh? Southern states such as Florida also rank high in this category, mostly because boaters there are less prepared.

H2O Horrors
By far the greatest danger of winter boat damage comes from water, which is one of the rare liquids that expands when it freezes. If you plan to use your boat year-round, and you live in a place where the temperature dips below freezing occasionally, you should winterize systems such as the water holding tank, showers, livewells, faucets and the head system — if your boat has them — and don’t use them during winter. It’s just too much of a hassle to winterize and recommission every time you want to go out. Take a bucket instead.

The other H2O-related issue is water in your engine systems. An outboard is easy. Tilt it down to drain it, and bump the starter to clear the water pump. If you have a closed cooling system, double check that your antifreeze solution is up to snuff. For a raw-water I/O or inboard, make sure, after every use, that you drain the water that lurks internally. Usually, there are drain plugs in the block and on the back bottom of the exhaust. After a few times performing this procedure, you’ll be a pro. Tilt the outdrive down and bump the starter to allow the water pump to fully evacuate.

Fogging Your Engine
The decision to fog an engine has nothing to do with the temperature and everything to do with its frequency of use. If you won’t be using the engine for more than six weeks, fogging it is pretty cheap insurance. When snowbirds leave their center consoles behind in Florida for the summer, they should perform a “winterization” to ensure internal parts don’t corrode. Hot, humid conditions greatly accelerate the process, so it’s probably more important to fog if you live in Miami rather than Denver, if the engine won’t be run.

Part of the problem with deciding whether you should fog lies in the fact it’s difficult to predict when you’ll use your boat next. Sometimes, a prolonged cold snap will cause a period of inactivity, but most often it’s the real world intruding into our boating lives that’s the problem. While you might have intended to go boating at least once a month, several months can slide by before you know it. One way to minimize the risk is to start your boat every couple of weeks, even if it’s using the old “fake lake,” aka ear muffs. Don’t leave muffs attached, however, as water might remain inside the engine during a freeze. Also, keep your batteries charged.

Give it to me Straight
For your winter fuel, fill ’er up with non-ethanol gas, to eliminate the possibility of phase separation, which happens after a few months when the ethanol sinks to the bottom of the tank and mixes with water (gas and water don’t mix). Because your fuel pick-up is located on the bottom of your tank, this hair gel-like goop gets “burned” first, which can lead to a catastrophic engine failure. Where can you find unadulterated gas? Go to and locate the nearest provider on the map. It’s pricy, though, often running $1 more a gallon. For a double-dose of protection, use an additive such as STA-BIL (the regular formula). If you can’t find ethanol-free gas, use STA-BIL’s marine formula.

Wet or Dry?
If you live in an area where you don’t get a lot of snow and the waterways don’t freeze, there’s a possibility you can leave your boat in the water. Table Rock Lake in Missouri is a good example. Residents in New York City routinely keep their boats in the water all year at places such as World’s Fair Marina, a short walk from the Mets’ stadium. There are several advantages to keeping your boat in the water. First, your boat’s systems that contain water are less likely to freeze than boats in rack storage, because of the higher ambient temperature. Another plus is the fact you can hop in the boat and go, which lends itself to taking short trips. Using an engine-compartment heater like those made by Xtreme will help protect your I/O motor. Obviously, you have to be able to take immediate action and yank your boat in case the temperature plummets or a storm is predicted.

One thing to keep in mind is that boating in cold water requires greater vigilance and more attention to safety, because a person who falls overboard in 40-degree water can be incapacitated in minutes. But the benefits are huge if you can keep your boating dream alive all year.

10 thoughts on “To Winterize or Not Winterize…

    • There are a lot of variables to this answer. Sometimes nothing happens, other times you have broken pipes due to expansion. There’s only one way to find out. Try it and see if it works. If you have a problem, take it to your dealer.

  1. I had my lower unit replaced late summer 2016 and the motor has not been in water since. Engine oil was replaced fall of 2015 and we put approximately 40 hours on the motor this summer and was not replaced when my lower unit was repaired. Is there any reason as to why I would need to winterize my motor if my lower unit has not been in water yet? Live in northern MN.

    • Replacing the outdrive doesn’t remove water remaining in the engine, and it is the water in the engine that will freeze and crack the block. So yes, you must deal with the water in the engine. Per the article above, you must also address the fuel issue.

  2. I bought a 1983 Thompson 21ft I/o 5liter engine. Hasn’t been run in years. I rebuilt the carb,changed belts,gas lines,v belts.Hasn’t been started yet. Do I need to winterize? Since it hasn’t been run in years,wouldn’t the damage already been done? Figured I’d deal with starting,etc in the spring.thoughts?

  3. i just bought my first boat and want to winterize. for the fist time… my friend told me to leave the block without water all winter that nothing happen to the motor…that is true

  4. I just got my boat storage in a warehouse that is heated and
    is not under 50 degrees all winter long.
    Do i need to winterize it?
    What should i do, so i have no problems spring time?

  5. I have a 1983 Volvo penta aq125a do I need to Winterize it or no I got all the water out of the copper lines and the raw water pump I also have a block heater and two heat lamps running at night time when the temperature drops below freezing lmk what I should do thank you

  6. Hey i live in NC and have a Yamaha115 out board engine that is in the water, not on a lift. (water never freezes down here) Do i have to worry about the lower unit if the engine is down in the water and not on a lift? i just ran the stabilizer through it and thats it because i like to go fishing in the winter.:) Am i ok?


  7. If you live in an area that doesn’t freeze that often, why not just keep a heating system on onnthe boat to keep anything from freezing?


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