With minds full of memories and a boat strewn with floats, fishing gear, and other fun baubles, you and your family have had a great summer. But now it’s time to start preparing your pontoon boat for winter, so you’ll be ready for next season.

Winterizing your boat will not only make things simpler when you’re ready to take it out again — it will also help protect your investment! Boats are subject to a host of potential threats, from mold and mildew, to rodent damage, to vandals and thieves. You’ll be glad that you took the time and effort to protect your boat from these headache-inducing problems.

Many dealers and marinas offer winterizing services, but the process is not too difficult to do yourself. This guide will walk you through six steps to winterize and store your pontoon boat. (Be sure to check the manufacturer owner’s manual for any guidance specific to your particular boat, particularly regarding your engine.)

1. Clean the Boat

Cleaning your pontoon boat is essential, for several reasons. Dust, grime, and barnacles are much harder to get off after they’ve “baked” on for a while. Mold and mildew will take up residence if they find moisture inside. And stray food particles will attract rodents and insects.

Inside the Boat

Start by removing unmounted accessories and equipment, like floats, fishing gear, depth finders, audio players, watersports equipment, ladders, etc. You’ll prevent damage to these items as well as take away breeding spots for mold and mildew, since moisture can easily become trapped in these objects.

Be sure to remove all electronics from the boat, for protection against thieves as well as protection against the elements. Electronics are tempting, and thieves know how to quickly unmount and steal them.

Next, vacuum the floor and cushions, making sure to get down into all the cracks and crevices. Get rid of all crumbs and anything that could serve as a food source. Wipe down all surfaces with a mild polish and then let dry thoroughly.

You may want to place rodent repellent to discourage pests from making a home in your pontoon boat. Traps aren’t necessary — you can use natural options, like spraying peppermint oil in cracks and corners. Peppermint has the added bonus of providing a wonderful scent when you uncover the boat in the spring.

Outside the Boat

Once you’ve prepared the inside of the boat for winter storage, you’re ready to tackle the outside. Begin by dislodging plants, mussels, barnacles, and other material.

Next, spray the boat down and wash with a mild detergent. (A pressure washer is helpful for this task, and makes quick work of it!) You’ll need to remove all the stuck-on grime that could get ground into the paint. Once the outside is clean, you can then apply a polish to the pontoon tubes that will protect the boat from rust.

2. Winterizing the Boat Engine

Before you jump into engine preparation, you’ll want to check your owner’s manual for specific instructions — this is especially important for engines, since they vary and an engine is a sensitive piece of machinery.

Most engines will follow basic guidelines for winterization, so unless your manual specifies something different, you’ll follow these steps.

  • For outboard engines, disconnect the battery.
  • For inboard/outboard engines, drain the engine block according to the manufacturer’s instructions.
  • Spray fogging oil into the carburetor, down the spark plug holes. Remove the spark plugs, spray the fogging oil, then replace the spark plugs without connecting the wires. The oil will offer a protective coating.
  • Fill the gas tank at least ¾ full. If the fuel has ethanol in it, add a fuel stabilizer to prevent buildup (which will wreak havoc on your engine later). This step will also reduce empty space inside the tank where condensation could accumulate and will reduce temperature fluctuations.
  • Drain the coolant from the engine and fill with an antifreeze that is propylene glycol based. (Note that you shouldn’t use antifreeze with an ethylene glycol base, since it can release toxins into the water.)
  • Switch off all valves and seal exhaust ports to prevent corrosion.
  • Change the oil and the oil filters.

3. Remove or Disconnect the Battery

When it comes to the battery, you have a decision to make. You can either leave the battery on board, or remove it for the season. Either option works, but you’ll need to prepare the battery differently depending on which one you go with.

If You’re Removing the Battery

If you want to remove the battery, fully charge it and then store it indoors. You can store it in your garage, as long as you ensure the temperature stays above freezing. Other good locations are a basement or heated outbuilding. You’ll also want to top off the charge throughout the winter.

If You’re Leaving the Battery On Board

If you decide to leave the battery on board, disconnect it and connect it to a trickle charger to keep the charge from draining. (You’ll need the bilge pump to be able to continue functioning if necessary, and the trickle charger will ensure it has enough battery power to do so.)

4. Cover the Boat

While a tarp is better than no cover at all, a pontoon boat cover that’s specifically designed for your make and model of boat will best protect your investment. A cover that’s built to withstand the elements and protect your boat from cold temperatures will give you peace of mind that your boat will be ready for you next season.

It’s a good idea to place a few poles underneath the cover to allow air to circulate, preventing mildew and mold. Many boat owners also run a dehumidifier. Poles will also prevent water from pooling on the cover and weighing it down.

A quality cover will fit your boat snugly and will expand and contract slightly to prevent temperature changes from creating rips. When applying the cover, be sure the cover is tight, but not too tight — or it may rip.

5. Keep Your Boat Secure

Now that your pontoon boat is protected from Mother Nature, you’ll need to protect it from thieves and vandals. Security should be a priority, whether you’re storing your boat at a facility or in your own yard. Vandalism can happen anywhere.

Still considering storage options? Check out our guide comparing wet slip, dry rack, and trailer storage.

Keeping your boat secure is primarily a matter of taking a few simple safety precautions.

  • If you haven’t dismounted and removed electronics as recommended in Step 1, be sure to do that now.
  • If you’re storing the boat on a trailer, put the trailer on blocks and remove the tires — this will prevent your boat from being hooked up and wheeled away. Alternately, you could install a tongue lock.
  • Check your insurance policy. Most basic property coverage plans will only cover the theft of the boat and major parts like the engine and fuel tanks. If you have a basic plan, you’ll probably be out of luck if accessories or other detachable items are stolen. You may want to chat with your insurance agent to find out the details of your policy and/or to purchase additional coverage.

6. When Spring Arrives, De-Winterize

When winter is over, and you’re ready to get your boat back out on the water, it’s time to de-winterize! This is the exciting part, because you know that fun with friends and family is right around the corner.

First, uncover the boat and check for any dents, leaks, or other damage. A good storage location and cover should have protected your boat from these problems, but it’s smart to search for any issues. You’ll want to get those taken care of right away so they don’t become worse.

Next, examine your cover. Are there any tears or holes? Again, a high-quality cover should be able to handle wear well, but now is the best time to search for damage — before you need the cover again. Allow the cover to dry thoroughly, then place it in its storage bag or duffel.

Reinstall your electronics and replace all your accessories and other items that you want to have easily accessible on your boat. Test all your electronics to make sure they’re working properly — especially your GPS system, because you won’t want to be stuck out on the water without it.

If you like, polish up your pontoons for a shiny finish. Any boat is more attractive when the aluminum is shining bright!

Wrapping Up

As you can see, winterizing your boat does take a bit of planning and time. Thorough preparation will keep your boat looking good and functioning well, for many years of enjoyment.

While some boat owners will choose to have their boats professionally winterized, DIYers should feel confident that they can prepare and protect their boats on their own. And once you’ve done it the first time, you’ll feel confident in the process next season!

Next Article: 18 Ways To Combat Mold and Mildew in Your Boat