Depending on where you live, winter months can be cruel to your boat. The corrosion, cracks, and damaged electronics highlight just a few of the issues boats face every winter. Learning how to winterize a boat might seem like a hassle, but doing so will save you money and time in the spring when you’re ready to get out on the water again.
Just a heads up, every boat model and manufacturer will have slight differences in its design and location of certain parts. This article will serve as a general overview of the essential steps needed to winterize a boat with an inboard or outboard motor. If you can’t locate specific parts on your motor, consult your owner’s manual.
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Where Will You Store Your Boat?
This might seem like a simple first step, but how to best winterize your boat will depend on where you plan on storing it. For example, some people might pull their boat out of the water and store it in a heated garage over the winter. If you plan on doing this, your winterization will be a lot easier than the rest of us. Nobody we know up here has this kind of luxury, but we can definitely dream!
For the sake of this article, we’ll be assuming you plan to store your boat either outdoors, or in an unheated shelter.
And by the way, my parents store our boats in the parking area of our property, the same place we park our family trucks, ATVs, and snow machines. Since it gets so cold up here - down to -48 C and even colder in some years, proper boat winterizing is especially important. We include it as part of our off grid winter prep routine.
Cleaning The Hull
When you pull your boat out of the water and onto your trailer, your first step will be to clean the hull and drain away any water still in the boat. Once you have it out of the water, open all seacocks and drains before you start washing.
Use a pressure washer to completely clean the hull of the boat, removing any barnacles, residue, or other dirt. We use a gas pressure washer because we live off the grid. You'll find electric pressure washers are a bit cheaper.
Keep an eye out for any cracks or blisters on the hull. If you notice cracks, have them looked at by a professional. If you notice blisters, follow these steps on how to repair fiberglass blisters at home from Boat US.
Once you’ve thoroughly cleaned the hull, you may want to apply marine wax . It’s not a requirement for winterization, but since you have the boat out of the water and clean already, you might as well wax it. Plus, it will help protect your hull and keep any dirt build-up easy to clean off.
Finish pressure washing the boat by cleaning the prop, shaft, rudder, and other areas you notice significant barnacle or scum build-up. The areas applicable to pressure washing will vary between inboard and outboard motors, so use common sense when cleaning on your particular boat.
Picking a Boat Cover
Covering your boat properly will help prevent ice and moisture from finding its way into your vessel and destroying it from the inside out. Ice can split seals and create cracks, leading to leaks in your boat. Moisture will lead to mildew and mold or create corrosion in your electronics and wiring on board.
If you already have a full-sized cover for storing your boat, that should be fine. Double-check it to make sure there’s no tears or areas that will be left uncovered. Your cover should fully protect the boat from letting any large amounts of water and ice in. However, make sure you leave a few openings from the side or underneath to allow for a bit of airflow while in storage. This will prevent mildew and mold from spreading with the trapped moisture. Additionally, use a marine mildew spray on your interior vinyl and controls for an extra layer of protection.
If you don’t have a fitted cover, shrink wrapping might be the best option for you. Many companies offer shrink wrapping services, but you might as well do it yourself to save a bit of money and hassle. The Shrinkfast Heat Gun is a great option for do-it-yourselfers, and Dr. Shrink’s website has many great tutorials and resources on shrink wrapping for different designs and sizes of boats.
How to Winterize a Boat With an Inboard Motor
As you might expect, winterizing a boat with an inboard motor will take a bit longer than it would with an outboard. To start, run your engine for a few minutes to get it warmed up to operating temperature. Once warm, shut it off, drain the oil and replace it with fresh oil. If needed, change the oil filter as well.
Next, flush your engine with fresh water. Once completed, you need to run anti-freeze through the manifold. Connect a hose from the water pump to a bucket of anti-freeze, turn the engine back on and let it circulate the anti-freeze until water begins to leak from the exhaust. Filling inboard motors with anti-freeze is necessary to stop small ice pockets from forming in the engine block and cracking it.
Remove any spark plugs to store inside over the winter, and wipe down any accessible areas of the motor to keep it clean. Spray any electrical connections with a moisture repellent treatment, and the entire engine with an anti-corrosion treatment. Remove the batteries and store them somewhere warm. Lastly, spray fogging oil into each cylinder to protect the insides from corrosion.
How to Winterize a Boat With an Outboard Motor
To start, remove the engine cover and check all hoses and connections for fraying, degradation, or cracks. Turn the engine on and run it up to operating temperature. Next, change the oil and oil filter.
If your outboard has an attachment for garden hoses to flush the system, hook one up and get started. If not, use one of these universal outboard motor flushers. Use fresh water to cleanse your motor, and run the engine in idle while flushing until the water exiting appears clean. Make sure to position your motor fully vertical to ensure it completely drains all traces of water. (it should be stored this way too)
Disconnect the fuel hose and run the engine until it burns through all the remaining fuel in its system and shuts off. At the bottom of the carburetor float bowl, you should see a drain plug. Remove it and let any remaining traces of fuel to drain from the engine. This is important because even the smallest amount of fuel left in your motor will gum it up and give you issues next spring.
Before you forget, add a fuel stabilizer to your now disconnected marine fuel tank to keep it from going bad while sitting for so long. Just like with inboard motors, you need to spray fogging oil into the cylinders to protect the internals from corrosion.
Storing Your Boat For The Winter
Before you cover your boat and forget about it for the winter, do a last inspection of the interior and exterior. Make sure you’ve removed any easy-to-access electronics, valuables, safety equipment, or other parts that won’t hold up well in the cold. Ensure the cover you’ve decided to use covers the entire boat all the way down the sides to where the water line would usually sit. It should be fastened tightly to prevent wind from tearing it or pulling it off.
Also, to be certain you didn’t forget any winterization steps, you should use a checklist. This one from Popular Mechanics covers all the things you need to remember for outboards, inboards, and sterndrives.
Lastly, check your owner’s manual to see if any additional winterization steps need to be done for your specific make and model.
If you follow these basic steps to teach yourself how to winterize a boat, you will be in good shape once spring arrives. A properly winterized boat will save you maintenance and repair costs for years to come, and extend the lifetime of your vessel.
Do you have any boat winterization techniques you like to use in your area? Let us know in the comments below what works (and doesn’t) for winterizing your boat.
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