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Storing your boat outside over the winter is perfectly fine as long as you control three things: moisture, temperature extremes, and security. Clean every surface, drain every system, seal the hull in a breathable but weather-tight cover, and keep an eye on the boat all season. Do that, and spring commissioning will be little more than adding fuel and turning the key.
Why Outdoor Winter Storage Deserves Extra Care
Freezing water expands with extreme force – enough to crack engine blocks and push hull fittings loose. Snow loads compress upholstery and hatches, while ultraviolet light and road salt (if you trailer) fade gelcoat and canvas. A few hours of preparation now can prevent big repair bills later.
Prep Your Boat for Outdoor Hibernation
Run, Inspect, and Jot Down Repairs
Take one last cruise. Listen for odd noises, note slow cranking, and mark gel-coat dings with painter’s tape so you can fix them on a warmer day.
Deep-Clean from Keel to Console
- Use biodegradable soap and a soft brush on the hull.
• Vacuum lockers and wipe vinyl with a mildew-inhibiting cleaner.
• Let every compartment air-dry completely; trapped dirt holds moisture that freezes and stains.
Drain Every Drop
Pull the drain plug, raise the bow, and let bilge water stream out overnight. Pump freshwater tanks, live-wells, heads, and raw-water washdowns. A dry boat is a safe boat when temperatures dive below 32° F.
Winterize the Engine
- Flush with freshwater to remove salt or silt.
- Stabilize the fuel – a full tank with a marine fuel stabilizer cuts condensation.
- Change oil and filters after a short warm-up run; warm oil carries out the impurities.
- Fog cylinders and drain the raw-water side, then back-fill with antifreeze.
Battery and Electronics Care
Top off the charge, grease the terminals, remove the batteries, and store them in a dry room above 50° F. Label and bag small electronics – multifunction displays, handheld VHFs, even stereo heads – so winter condensation can’t reach delicate circuits.
Lubricate Moving Parts
Grease steering cables, throttle linkages, seacocks, hinges, and latches. A dab of marine grease now keeps parts from seizing after months of sitting still.
The Cover Rule: Tight, Vented, Sloped
A cover that sags will funnel water into the cockpit; a cover that’s airtight will trap moisture. Build a simple ridgepole frame or inflatable support, then add one of three protection layers described below.
Check In Monthly
Brush off snow, inspect tie-downs and vents, and spin the trailer wheels to keep hubs greased. Ten minutes every few weeks beats ten hours of repairs in April.
Choosing the Right Cover
| Option | Pros | Cons | Best For |
|---|---|---|---|
| Shrink wrap | Hermetic seal, sheds snow | Annual cost ≈ $15–$20/ft, plastic waste; poor ventilation | High-end vessels or owners who can’t visit often |
| Big-box tarp | Cheap, easy to find | Tears, UV degradation, chafes gel-coat; must lash carefully | Short-term storage in mild winters |
| Reusable custom cover | Lasts 7–10 years, breathable panels prevent mold, fitted vents, better snow-shedding | Higher upfront cost | Long-term value, harsh-climate storage |
Bonus Tip: If you choose shrink wrap, ask the yard to install extra vents and always cut a small inspection “door” so you can unzip and air out the bilge on warm winter days.
Set the Boat on Land the Right Way
- Park on well-drained gravel or asphalt – frozen ground heaves.
- Chock tires and drop the trailer tongue slightly so rainwater flows aft and out.
- Add blocking under the transom so leaf springs don’t carry full weight for months.
- If you store on stands, place plywood under pads so they don’t sink when the ground thaws.
Special Considerations by Hull Type
Aluminum Fishing Boats
Galvanic corrosion accelerates when winter road salt sits on bare metal. Rinse thoroughly and wax paint below the rub-rail.
Inflatable RIBs
UV-protect the tubes with a 303-type spray and crack valves open a half turn so expansion and contraction don’t overstress seams.
Sailboats on Trailers
Slack standing rigging slightly; stainless wants to “relax” when not under load. Remove sails, fold loosely, and store indoors.
Cost vs. Convenience
Indoor heated storage can run $40–$60 per foot. A reusable winter cover averages $700 but spreads over a decade, saving thousands while still protecting the boat.
Winter Storage Checklist
- Final run and inspection complete
- Hull washed, waxed, and dried
- Bilge, tanks, and live-wells drained
- Engine flushed, fogged, and antifreeze added
- Fuel tank full, stabilizer mixed
- Batteries out, charged, and indoors
- Electronics, cushions, safety gear removed
- Moving parts greased
- Quality cover installed, vents open, ridgepole pitched
- Trailer or jack-stands secured, and tires blocked
- Monthly reminder set on your phone
- Sea Tow membership current
The Bottom Line
Storing a boat outside through the coldest months isn’t guesswork, it’s a checklist. Follow the steps above and you’ll spend spring launching – not fixing. And if you run into trouble on that maiden voyage, a quick call to Sea Tow can get you back underway fast.
Sea Tow Team
Sea Tow has been the premier leader in on-water boating assistance since 1983. We want to share news, press, tips and all things boating.