When to pull the boat — and what drives that decision
The conventional answer is before consistent overnight freezing temperatures arrive. In Ontario, that's typically late September to mid-October depending on the year and location. In British Columbia, coastal boats can stay in the water later, but interior lake boats face the same freeze risk as Ontario. Quebec and the Maritimes vary significantly by microclimate.
The practical answer is: before the first freeze after haul-out. Pulling the boat in late September means there's time to do the winterizing work properly before temperatures drop. Pulling in November in a rush to beat the freeze usually means something gets done incorrectly.
Haul-out is also determined by when the yard has lift availability. Most Ontario marinas have compressed haul-out windows in October, and booking early is straightforward — call in August.
Outboard engine winterizing
Outboard engines are the most time-sensitive winterizing task. Modern four-stroke outboards and older two-stroke motors both need attention, but the specifics differ.
Flushing the cooling system
Run the engine on flush muffs connected to a garden hose for five to ten minutes to clear lake or ocean water from the cooling passages. The thermostat needs to open for the flush to be effective — the engine needs to reach operating temperature. On engines with a telltale indicator, verify water is flowing before shutting down. Salt and mineral deposits left in the water jacket accelerate internal corrosion during storage.
Fogging the cylinders
Engine fogging oil — a light oil spray applied to cylinder walls — prevents corrosion on bare metal surfaces inside the engine during months of non-use. For carbureted engines, fog through the carburetor throat while the engine runs, then kill it with the choke. For fuel-injected engines, use the dedicated fogging port or apply through the spark plug holes after removal. Check the engine manual for the manufacturer's procedure.
Fuel system
Two approaches exist, and they're not compatible with each other:
- Run dry: Let the engine run until it stalls from fuel starvation. Works for carbureted engines; keeps the system clean. Requires restarting easily in spring, which may need fresh fuel and possibly carburetor adjustment.
- Stabilize: Add fuel stabilizer to a full tank, run for ten minutes to circulate treated fuel through the system, then store with the fuel in place. Better for fuel-injected engines where running dry isn't recommended.
Regardless of approach, remove the engine from the transom or tilt it fully vertical so any water remaining in the lower unit drains. Check the lower unit oil for milky or water-contaminated color — if it's anything other than clean gear oil, the lower unit seals need replacing before spring launch.
Battery storage
Marine batteries discharged below 50% during storage may not recover. Remove batteries from the boat, bring them indoors, and put them on a maintenance charger that provides a float charge rather than a trickle charge. A flat-rate trickle charger left connected through the winter can overcharge and damage batteries. Most auto parts stores carry appropriate maintenance chargers at moderate cost.
Engine inboard and sterndrive winterizing
Inboard engines and sterndrives have more water passages than outboards and require antifreeze in the cooling circuit for Canadian winters. The standard approach for raw-water-cooled inboards is to flush the system with a propylene glycol antifreeze solution — not ethylene glycol, which is toxic to marine environments. The antifreeze flush displaces residual water in the heat exchanger, exhaust manifold, and water pump housing.
Sterndrives need the lower unit lubrication changed at haul-out (not spring launch — the reason is that water that has infiltrated the lower unit over the season will cause corrosion if it sits all winter). The bellows — flexible rubber boots connecting the sterndrive to the transom — should be inspected for cracks or delamination; failed bellows allow water into the bilge.
Interior and bilge preparation
The interior objective is to remove moisture sources and allow airflow that carries remaining humidity out of the boat. Standing water in the bilge is the starting point — pump it dry and then dry the bilge with rags. A wet-dry vacuum reaches corners and the spaces between floor boards that sponges miss.
Remove everything that can absorb moisture: cushions, mattresses, life jackets, fabric storage bags, food, paper charts. These items stored aboard trap humidity and promote mildew growth that's difficult to eliminate the following spring.
Leave lockers open. Prop drawers open. Remove companionway boards or leave a screened vent in place to allow airflow. A few moisture-absorbing desiccant containers placed in the bilge and main cabin area help manage residual humidity. Avoid fully sealing the boat with shrink wrap without some form of venting — a fully sealed boat with residual moisture will produce significant mold.
Cradle and blocking for hull support
Fiberglass hulls are not designed to rest on their keels for extended periods without lateral support. A hull stored on a flat keel without adequate side support will deflect — sometimes enough to cause permanent deformation in the bilge stringers or show as hard spots when the hull is back in the water.
Proper cradle support involves:
- Keel bearing: The keel stub should be supported along its full length, not just at the front or back.
- Side pads: Cradle arms should contact the hull at multiple points along the bilge, not just under the turn of the bilge at one location. Pads should be carpeted or padded to prevent point loading on the gel coat.
- Cradle angle: The cradle should hold the boat at its designed waterline angle — not tilted aft (which pools water at the transom and stresses the keel-hull joint) or forward.
- Stability check: Give the stored boat a firm push fore and aft and side to side. If it rocks, the cradle needs adjustment before leaving it unattended over winter.
Mast — stepped or pulled?
On a trailerable sailboat or small keelboat where the mast comes down easily, pulling it for winter is straightforward: remove it, check the masthead fitting and all hardware, wash it, and store it horizontally supported at multiple points to prevent sagging. On a larger boat where stepping requires a crane, the decision involves cost and timing.
Arguments for leaving the mast stepped through winter storage: cost savings, no risk of mast damage during crane operations in cold weather. Arguments for pulling it: opportunity to inspect the masthead in detail, replace worn windex or wind instruments, re-seal masthead fittings, and inspect internal halyards and wiring. For boats with aging or suspect standing rigging, winter with the mast down is the right time to replace wire before the following season.
Shrink wrap versus tarp cover
Shrink wrap provides a tight, weatherproof cover that sheds snow load efficiently and doesn't flap in wind. The downsides are cost and the plastic waste generated at spring haul-out. A properly fitted tarp with ventilation allows reuse but requires checking after each significant storm to ensure it hasn't shifted and collected water pooling on deck.
Either approach should include a forward vent to allow air exchange. Shrink wrap installations for marine storage are typically done by the yard rather than boat owners, and good yards include vents as standard practice.
