The Ultimate Flathead Valley Boat Winterization Checklist


As the vibrant summer days in the Flathead Valley give way to the crisp autumn air, boat owners know that the season of picturesque lake days is drawing to a close. While the memories of sunny afternoons on the water will last, the impending cold of a Kalispell winter means it's time for one of the most crucial responsibilities of boat ownership: winterization. In a region with a continental climate characterized by cold, snowy winters where temperatures can plummet to 17°F or even lower, proper boat winterization isn't just a suggestion—it's essential for protecting your investment. This is where Stillwater Storage, located right here in Kalispell, MT, comes in, offering the peace of mind that your boat is safe and secure. Here's our ultimate checklist to guide you through the process.


Why Winterize Your Boat in Flathead County?

The freeze-thaw cycle in Flathead County can wreak havoc on a boat that's not properly prepared. Water left in the engine block, plumbing, or other systems can freeze, expand, and cause catastrophic damage, leading to costly repairs come springtime. Beyond the engine, the harsh winter elements can damage the hull, upholstery, and electrical systems. A thorough winterization process ensures that when the warm weather returns, your boat is in pristine condition and ready for another season of adventure.


The Comprehensive Boat Winterization Checklist

Follow these steps to ensure your boat is ready for its winter hibernation:

1. Engine and Fuel System:


Fuel Stabilizer: Fill your fuel tank to about 90% capacity to prevent condensation, then add a quality marine fuel stabilizer. Run the engine for 10-15 minutes to circulate the stabilized fuel through the entire system. 

 Change the Oil and Filter: Warm oil drains more effectively, taking more contaminants with it. Changing the oil and filter now prevents corrosive agents from damaging your engine over the winter. 

 Fog the Engine: For inboard and sterndrive engines, "fogging" the engine with a storage seal spray coats the internal components, like cylinders and pistons, with a protective layer of oil to prevent rust and corrosion.

Antifreeze: Drain the engine block and cooling system completely, then circulate a marine-grade propylene glycol antifreeze through the system. Never use automotive (ethylene glycol) antifreeze, as it's toxic to aquatic life. 

2. Plumbing and Water Systems:


 Drain All Water: Completely drain any onboard freshwater systems, including tanks, pumps, and heads. Open all faucets and spigots to ensure every last drop is gone. 

 Add Antifreeze: Run a non-toxic, marine-grade antifreeze through the plumbing system until you see the colored antifreeze coming out of the faucets. This will protect your pipes from freezing and cracking. 

 Bilge Pump: Ensure the bilge is clean, dry, and free of debris. A small amount of antifreeze in the bilge will protect the pump if any water remains. 


3. Interior and Exterior Cleaning:


Thorough Cleaning: Clean the boat inside and out, removing any dirt, grime, or algae. This prevents staining and mildew growth.

Remove Valuables and Electronics: Remove all personal items, valuables, and sensitive electronics. Store them in a safe, dry place at home. 

Upholstery and Canvas: Clean and dry all upholstery, cushions, and canvas. If possible, store them at home in a climate-controlled environment to prevent mold and mildew. 


4. Battery and Electrical:


 Disconnect and Store: Disconnect the battery cables, and if possible, remove the batteries. Store them in a cool, dry place, and consider connecting them to a trickle charger to maintain their charge throughout the winter. 


5. Secure and Cover:

High-Quality Cover: Use a high-quality, breathable boat cover that can withstand the weight of snow and ice. A good cover will protect your boat from the elements while allowing for proper ventilation to prevent moisture buildup.

The Final Step: Secure Storage with Stillwater Storage

Once your boat is winterized, the final and most crucial step is securing a safe storage location. While some may opt to keep their boat on their property, the best way to protect your investment from the harsh Montana winter is with professional storage.

Stillwater Storage, conveniently located at 135 Barkley Ridge Trail, Kalispell, MT 59901, offers a variety of storage solutions perfect for your boat. We provide a range of unit sizes, from our 14x40 to our spacious 15x50 units, ideal for boats of all sizes. For those looking for the ultimate protection, our Climate-controlled Storage options ensure your boat is shielded from the extreme temperature fluctuations of a Flathead County winter.

At Stillwater Storage, we don't just offer boat storage; we provide peace of mind. Our facility is equipped to handle all your storage needs, including RV Storage, Vehicle Storage, and self-Storage Options. Don't leave your prized possession to chance this winter. Contact Stillwater Storage today to learn more about our storage solutions and how we can help you protect your investment for years to come.