What should you know about boat winterization?

How Important is Boat Winterization?

Freeze damage is the most significant possible concern of your boat during the winter season. The water that comes in and out of your boat also offers corrosion as well as mold and mildew development. It’s essential to keep the water and moisture out as much as possible. Moreover, never miss paying attention to the following once you perform boat winterization:

  • Boat’s engine
  • Plumbing systems
  • Fuel systems
  • Other systems that hold water

Winterizing Your Boat’s Outboard Engine

Compared to popular theory, boat winterization doesn’t mean winterizing just the boat. You need to winterize the inside and out of your boat. It includes the parts that make your water vessel function and run smoothly, particularly the outboard engines. Also, don’t forget to check the manufacturer’s instructions before winterizing your boat by yourself.

The outboard engines are specifically designed to drain all the water from its cooling system thoroughly. You need to tilt the engine down and cover it. Make sure that there’s sufficient ventilation to prevent condensation build-up.

Additionally, it’s essential to give your outboard engine’s internals some shielding from corrosion as it nestles. For two-strokes and carbureted outboards, fogging oil should run through the machine. Modern outboards, on the other hand, use a much easier “fogging” procedure.

Other people believe that the best way to winterize an outboard is to keep using it. What causes outboard issues are extended periods of inaction and not low temperatures.

Winterizing Your Boat’s Stern Drive

Stern drives are more complicated than outboard engines to winterize, as you need to remove the water from the engine’s block and drive unit. Besides, you might need to run antifreeze through the drive and motor.

You might also have to remove block plugs during the winterization process. This allows water drainage from the engine. At the same time, it helps eliminate scale and sediments that collect inside. Don’t forget that an oil change is also necessary for boat winterization.

Furthermore, inspect any exposed hoses, clamps, bellows, and other worn parts. Note that stern drives also require fogging treatment. Before doing it, run the engine to its operating temperature. It will help dry out any remaining moisture in the engine.

Winterizing Your Boat’s Inboard Engine

Your inboard engine requires the same treatment as your boat’s stern drive. You can somehow remove the drive system from the procedure. Drain the engine by opening petcocks or by removing the plugs. You can also run antifreeze through the system.

Other boat owners leave their boats in the water for winter. If you’re doing the same, you need to perform antifreeze through the system. Close the intake seacock and take off the intake hose from it.

Submerge the hose’s end in a bucket of antifreeze. Start the engine to its running temperature. Wait for the antifreeze to come out from the exhaust ports.

Remember to wait for the engine to reach its operating temperature before doing antifreeze. If not, the thermostat will cut off the flow to some cooling passages up to the engine’s operating temperature.

Remember that inboards also need a fogging treatment, just like other engines. You can do an oil change and inspect any parts that need already need a replacement.

Winterizing Your Boat’s Fuel System

Regardless of what kind of boat you have, it still needs winterizing. Your boat’s fuel tank requires an excellent fuel-stabilizing additive. Don’t use ethanol-blended fuel, or you’ll have water-saturated fuel issues.

Make it a habit to constantly replace the whole canister and don’t re-use. It’s because water and debris can accumulate on the filter’s wrong side. This happens once you pour it and becomes deep-set into the system. It could lead to the filter’s internal components’ damage.

Winterizing Your Boat’s Plumbing System

Last but not least is winterizing your boat’s plumbing system. It includes tanks, sinks, and heads that need total drainage. You need to open all faucets to drain the water until the tank is dry. Afterward, close all the faucets back and run a non-toxic antifreeze through it.

Open the faucet that’s farthest from the tank. Allow the antifreeze to leak out and then close it again. Next, open the next-farthest tap and do the same procedure. Do this until all antifreeze come out.

Don’t also forget to pump out holding tanks. Pump antifreeze through the head or heads on your boat. Remove the portable MSD and empty it in case your boat has one. You must do this, or you’ll have a smelly ship in the following spring.

It’s worth noting that water expands about 9% in volume once it freezes. It can damage the rubber hoses, tear iron, or break iron. This is the main reason why you need to drain all of the water from your boat’s system before running antifreeze.


As a boat owner, boat winterization is an integral part of maintaining your watercraft. Proper maintenance helps prolong the life of your marine vessel. Winterizing your boat before winter can help save you costly repairs and maintenance. If you have some trouble doing boat winterization yourself, you can have it serviced to save you time, effort, and money.

Lakeside Marine and Watersports can help you out in preparing your watercraft for the cold winter months. We offer a comprehensive winterization process at affordable prices. Talk to our team today to set an appointment and get your boat perfectly winterized.

Ella Smith has been a brilliant writer and her writing is impressive. She often writes for Educational and motivational topics that is a great point in her. She has started writing for Brightshub for a couple of months.
Translate »