Winterizing A Boat: What You Need To Know

All boaters who live in cold winter climates understand that winterizing your boat engine is essential to make sure the engine doesn’t freeze. However, there are many questions people may have surrounding the issue.

In this article, I go over any questions you may have about winterizing a boat. Use the table of contents below to click on the questions you want to see the answer to.

Do you have to winterize a boat?

If the air temperature around your engine drops below 32°F (0°C), you will need to winterize your engine. However, you don’t have to winterize the engine if you store your boat in a heated garage that doesn’t drop below that temperature. Or your live somewhere that doesn’t ever freeze.

What happens if you don’t winterize your boat?

If you don’t winterize your boat engine and the air temperature falls below freezing 2-3 days in a row, the liquid in your engine will freeze and break the engine.

What happens if your boat engine freezes?

When your boat engine freezes because you didn’t winterize it or get it into a heated facility on time, many parts of it will break. Liquid expanding from being frozen will cause rubber hoses to split and metal to crack. It would cost a lot to get it fixed.

When should you winterize a boat?

You should winterize your boat right after the last time you take it out for the season. Don’t wait until the temperatures start dipping down to near freezing, it’s not worth the risk. Many mechanics may be too busy to get to your boat on time if you wait too long.

Technically as long as you get your engine winterized before the temperatures drop below freezing, it should be fine. However, temperatures are unpredictable, and 2 or 3 days below freezing in a row could cause your engine to freeze.

Along with that, many boat mechanics may be backed up with other winterizing jobs and may not be able to get to your boat until it’s too late. So I recommend not risking it and getting your boat winterized early (or at least schedule it early).

I live in Wisconsin and generally get my boat winterized in late September as I don’t ever use my boat any later than that. However, if you lived farther south, you could probably extend this into October-November and be fine.

How long can a boat sit without being winterized?

If there are 2-3 consecutive days and nights of sub-32°F (0°C), your engine will freeze unless it’s winterized. However, if it only dips below freezing at night and gets warmer than 40 during the day, you should be fine, especially if the water temperature is above freezing.

If you need to let your un-winterized boat sit in freezing temperature, I recommend putting a 125-250 watt incandescent light bulb in the engine compartment. This should keep the temperatures above freezing, but don’t use this as a permanent winterizing option.

This heat lamp on Amazon meant for chicken coops would work great.

How much does it cost to winterize a boat?

After getting 10 different quotes from boat mechanics from all across the US, I determined the average cost to winterize a boat.

To hire a professional to fully winterize a boat (including winterizing the engine, changing gear and engine oil, and shrink wrapping), it will cost around $500 to $1,700, depending on the size of your boat and type of engine. However, if you winterize a boat yourself, it’ll only cost $200 to $575.

Because outboard engines don’t need to be flushed with antifreeze, it’s generally $75-$250 cheaper to winterize them. The price mostly depends on if you hire a mechanic or do it yourself.

Another small price to consider is purchasing fuel stabilizer, which only costs around $20.

If you want to see the price of all these different sub-categories to winterizing a boat, read below:

Cost to winterize just the engine

If you hire a professional to winterize your boat engine for you, it will cost around $200-$500, depending on the size of your boat. If you do it yourself, it will cost around $75-$150 and take you about 4 hours to do.

If you want to make sure it’s done right and don’t want to spend the time, I recommend hiring a mechanic. However, it isn’t that difficult to do it yourself, and you’ll save a lot of money. Sometimes the time it takes to bring your boat to the mechanic and back will be just as long or almost as long as if you just winterized it yourself.

Cost to change gear and engine oil

It will cost around $75-$125 to change your boat’s engine and gear oil yourself and take 2-4 hours. You can hire a mechanic to do it for $250-$600.

Every 2-3 years (depending on what your manual recommends) you should also change your impeller during this time. That generally costs $100 to do yourself and mechanics charge around $200-$300.

Cost of winter storage and shrink wrapping

Shrinkwrapping your boat costs around $10-$20 per foot, which correlates to

  • 20-foot boats = $200-$400
  • 25-foot boats = $250-$500
  • 30-foot boats = $300-$600
  • 35-foot boats = $350-$700
  • 40-foot boats = $400-$800
  • 45-foot boats = $450-$900
  • 50-foot boats = $500-$1,000

If you shrinkwrap your boat yourself, it will only cost around $120-$300 and take you about 4 hours.

Another cost you will need to consider for the winter is storage costs. According to Discover Boating, it costs around $50-$200 per foot to store your boat in an indoor boat garage and $20 to $50 per foot to store your boat in outdoor storage.

How much does it cost to de-winterize a boat?

To de-winterize your boat from a mechanic, it will cost around $250 to $500 depending on how many services you want. De-winterization includes many different maintenance checks, so depending on what your boat needs the price could vary.

If you de-winterize your boat yourself, it will just take a couple of hours to refill the coolant system and check for any engine damage. It won’t cost money unless something is broken that you need to fix. Check out this article to see how to de-winterize a boat yourself.

How do you winterize a boat?

Winterizing your boat requires more than just draining the water, especially for inboard and I/O engines. Below I explain the 7 steps you need to follow to winterize your boat (steps 5 and 6 can be skipped if you have an outboard motor, just make sure you put it upright to drain all the water out).

Free to share this image on your website or social media, just give credit by linking to this article. Click here for the .png file.

If you want to watch a video to help you out, check out this one if you have an inboard or I/O engine:

And this one if you have an outboard:

What products do you need to winterize a boat?

Depending on the winterizing services you perform on your boat and what type of boat you have, the products you’ll need may differ. For example, outboard engines don’t need antifreeze, but inboard and I/O motors do.

Here are the products you’ll need to fully winterize a boat:

  • Fuel stabilizer. You need fuel stabilizer to make sure your fuel stays fresh during storage. I recommend getting this one on Amazon.
  • Engine oil. Check your owner manual, or check out this article to see what oil should be used for your engine. If you change the engine oil, you’ll also need an oil pump such as this one.
  • Lower unit lube. You should also check your owner’s manual to see what gear lube is recommended for your engine. However, this one here works for all outboards, jet pumps, sport jets, and Mercruiser sterndrives.
  • Antifreeze. Only inboard/IO boats need to be rinsed with antifreeze through the water pipes. I recommend getting this one as it is biodegradable so you can start your boat right up next season in the lake or ocean without harming anything.
  • Shrinkwrap and heat gun. If you plan on shrinkwrapping your boat yourself, you’ll need shrinkwrap and a heat gun. You can find both of those products by clicking here.

How do you de-winterize a boat?

De-winterizing your boat primarily includes making sure nothing on your boat is broken. You’ll most likely be able to start your boat up in the spring, and it will work unless something broke in storage. However, it may take a couple of cranks to get it going.

Here are the things you should check when de-winterizing your boat to ensure it’s not broken:

  • Make sure there is enough oil and gear lube
  • Check engine belts for cracks or loose connections
  • Check the water pumps for cracks or loose connections
  • Check the impeller for cracks and bends
  • Check hoses for cracks
  • Check cables for tears
  • Check fuel lines for cracks
  • Make sure bilge pumps are working
  • Make sure batteries are charged and maintained
  • Clean the distributer

You should also wax your boat before taking it out for the first time.

Can you leave a boat in the water during winter?

Yes, you can leave your boat in the water during the winter; however, you need to take proper precautions to ensure you don’t damage your boat. This includes winterizing the engine and gas tank, using a de-icer, keeping the battery charged, and covering the boat properly.

One thing to note is that if the electricity were to shut down in your marina and your de-icer were to stop, ice could quickly damage your boat. So to avoid that, make sure the marina has a backup power source for their de-icers.

You’ll also want to cover your boat by shrinkwrapping or covering it with its cover or tarp. Check out this article to learn more about winterizing a boat that stays in the water.

Do you have to winterize boats in southern states?

If you live in a southern state, sometimes winterizing may not be needed. However, for most states, there will be 2-3 consecutive days of sub-32°F (0°C) weather at some point during the winter. So it’s always recommended to winterize your boat to be safe.

The only places in the US that I wouldn’t recommend winterizing your boat is Florida, Southern California, and Hawaii. All other states can reach freezing temperatures during the wintertime.

According to, the top states that receive winterizing insurance claims are:

  1. Texas
  2. New York
  3. New Jersey (tie)
  4. Maryland (tie)
  5. Virginia
  6. Mississippi
  7. Georgia
  8. North Carolina
  9. Washington
  10. South Carolina

So, people need to be careful in southern states as a little cold wave could freeze your boat engine if it’s not winterized.