BoatU.S. Marine Insurance reported the following six most common mistakes made when winterizing a boat:
1. Failure to winterize the engine
Freezing temperatures occur in most states, and while they are taken seriously up north, it’s the balmy states of Florida, Texas, Georgia, Alabama and California where boaters are most likely to have freeze-related engine block damage.
2. Failure to drain water from sea strainer
If your winterizing plan calls for draining the engine, you must winterize the seawater strainer or residual water could freeze and rupture the watertight seal. Sometimes you won’t know the strainer has been damaged until water begins to trickle during spring launching.
3. Failure to close sea cocks
For boats left in the water, leaving sea cocks open over the winter is like going on extended vacation without locking the house. If a through-hull cannot be closed, the vessel must be stored ashore—the sole exception being cockpit drains. Heavy snow loads can also force your boat lower, allowing water to enter through-hulls normally well above the waterline. Make a checklist so you don’t forget to reverse the process in the spring.
4. Clogged petcocks
Rust or other debris can clog engine cooling system petcocks, preventing water from fully draining. If one is plugged, try using a coat hanger to clear the blockage or use the engine’s intake hose to flush antifreeze through the system.
5. Leaving open boats in the water over the winter
Boats with large open cockpits or low freeboard can easily be pushed underwater by the weight of accumulating ice and snow. Always store them ashore.
6. Using Biminis or dodgers as winter storage covers
A cover that protects the crew from the sun does a lousy job of protecting the boat from freezing rain and snow. Unlike a bona fide heavy-duty winter cover, Biminis and dodgers tend to rip apart and age prematurely when exposed to winter weather.