Winterizing a Boat: Everything You Need to Know
Winterizing a Boat: Everything You Need to Know
When old man winter is ushered in, consider these expert tips and information for winterizing a boat to ensure a hassle-free launch come next spring.
Keyword(s): winterizing a boat
Fail to winterize your boat, and you could face thousands in repairs.
The engine alone can easily cost $6,000. That’s just for one — replace two outboards and you’re looking at about $12,000 easily.
That’s just for the engines. It will cost even more to replace your freshwater tanks and lines, replace the upholstery, and hull repairs.
You can prevent all this. Winterizing a boat before the temperatures start to drop will protect your boat and ensure you have years of enjoyment ahead of you.
Here’s how.
Clean the Boat
The first step in getting your boat ready for winter storage is to clean it.
Your boat is going to spend a few months sitting, so don’t allow salt or anything else to corrode and eat away at your boat’s materials.
When finished, you’ll want to make sure the boat is dried thoroughly. Moisture sitting in an enclosed space is asking for mold and mildew to take hold.
You’ll know you have failed if you smell a terrible odor when you open the boat back up. Mold and mildew can ruin the upholstery in your boat. It will also cause respiratory problems to those who use your boat next summer.
Plan for Ventilation
One way you can prevent mold growth is to ensure there is plenty of ventilation.
You could use an active ventilator that will encourage the flow of air.
If you plan to shrinkwrap your boat, you can use passive vents. This will allow for the flow of air.
Consider Using a Heater
There is some controversy when it comes to using a heater.
If you have a power source, you can place a heater, dehumidifier, or turbo dryer in the engine bay or cabin of the boat.
You’ll need to be careful; there is a risk of starting a fire if you don’t place your heater in a safe place.
Place Moisture-Absorbing Crystals
You can buy crystals that will absorb the moisture in your boat.
Place the crystals in the cabin or other areas where moisture tends to gather. The crystals will suck the moisture out of the air.
Freshwater Systems
Do not leave any water in your boat untreated.
This water will drop in temperature, freeze and expand, and damage your boat. Now you have a cracked tank, fitting, pipe, or anything else.
The best thing to do is to drain the tank. You can use a portable pump to do this.
If this isn’t possible, you can pour in an antifreeze. You need to use enough to ensure all the water is treated. Do not fill the freshwater tank with antifreeze.
Filling the tank to the brim with antifreeze will only create a bigger project come spring. You’ll need to purge the tank of the antifreeze and clean it thoroughly.
Cover the Boat
You have four options for covering your boat:
- Plastic tarps
- Canvas tarps
- Fitted covers
- Shrinkwrap
You’ll need to use one of these covers whether you choose to leave the boat in the water or take it out.
The cover will protect your boat from UV rays and the weather elements.

A plastic tarp is the most affordable, but won’t last more than a season or two. They also flap in the wind if you don’t tie it down well enough.
A canvas tarp is better quality, but also more expensive. You still have the potential for flapping in the wind. You can expect them to last longer at four to five seasons.
The most expensive, protective, and durable option is a fitted cover. It is specifically made with your boat’s shape in mind for a custom-fitted shape.
Shrinkwrap is a plastic cover that is treated to shrink down over the boat. You’ve probably seen new boats delivered with this type of wrap. It is the most secure, but you also can’t get inside your boat without destroying it.
Treat the Fuel
The fuel in your system is only stable for a certain amount of time, and only in certain temperatures.
Leaving your fuel untreated will cause it to separate and your fuel injectors to get clogged. Ultimately, you’ll ruin the fuel system.
Pour in an additive that will stabilize the fuel, then let the engine run for a good ten minutes or so. This will ensure the entire system gets treated.
A few dollars and ten minutes now will save you thousands later.
Fog the Engine
Fogging the engine means you’ll use an aerosol solution to coat the inside of the engine.
This protects it during the winter months from corrosion.
There are plenty of options to choose from. Every engine manufacturer will push their proprietary formula as the best for their engines.
You’ll hook up your garden hose and run the engine. Then spray the fogging solution into the air intake until it’s gone.
It should cost you less than $20 for a fogging treatment. This is significantly less than replacing your engine or having it repaired.
Change the Oil
Replacing your oil helps remove moisture.
As with everything on this list, removing moisture prevents damage.
If you leave this excess moisture, you’ll experience excessive wear. This will lead to a loss of power and fuel economy. Then eventually you’ll have engine failure.
Drain the Engine
If you have a stern drive or inboard, you need to drain the engine.
Open the bronze plugs and remove the water pump hose. This will remove all the liquid that’s currently in the system.
If you have an older system, you’ll find the drains on the side of the engine block. If you have a newer boat, you may find it on the front of the engine.
If you don’t do this, the water in the cooling system will freeze. This will crack your engine block.
Doing this task won’t cost you anything. However, not doing it will cost you the replacement of your motor.
Be a Pro at Winterizing a Boat
By following this guide, winterizing a boat should be easy!
With a little bit of effort now, you can ensure your boat is ready to go next spring.
After all, the last thing you want is to discover that your boat needs extensive repairs when spring arrives.
Find out how much it will cost to have your boat wrapped as a part of your winterization.