Published: Wednesday, September 13, 2017
When I purchased my first inboard boat, a late-70s vintage Chris Craft cruiser, I was overwhelmed by the winterization process. I had always felt confident about putting my outboards and trailerable boats to bed for the season, but not the big inboard engine, let alone the complexities of the vessel’s water system. It was worth every dime in peace of mind to have the yard crew handle the winterization each autumn.
For those who are considering DIY winterizing this fall, members of the Boat Owners Association of the United States report, via their insurance claims, the following most common mistakes owners make when winterizing a boat:
Failure to Drain the Engine Block
Surprisingly, it's not the Great Lakes states where boaters are most likely to have freeze-related damage to engine blocks. States that aren’t often associated with sub-freezing temperatures are where the majority of the association’s claims originate.
Failure to Drain Water from Sea Strainer
As with the engine, the strainer must be winterized or residual water could freeze and rupture the watertight seal — which may go undiscovered until the following spring.
Failure to Close Seacocks
If a thru-hull can’t be closed, the boat must be stored ashore in the off-season, period. The exception being cockpit drains. Heavy snow loads can also force a boat under, allowing water to enter scuppers and thru-hulls that are normally above the water line.
Engine cooling system petcocks clogged by rust or other debris can prevent water from fully draining — allowing the remaining water to freeze and offering the threat of damage. Clear any suspected blockage using wires or use the engine's intake hose to flush anti-freeze through the system.
Leaving Open Boats in the Water Over Winter
Boats with large open cockpits and/or low freeboard can easily go under by accumulated snow alone.
Counting on Bimini and Convertible Tops to Serve as Winter Storage Covers
Unlike stout winter covers made to withstand the ravages of winter, such fair-weather tops tend to fail under ice and snow.
You can get a free copy of the BoatU.S. Winterizing Guide, which offers tips to help you prepare your boat at boatus.com/seaworthy and clicking on "Winterizing Your Boat," or you can call 800-283-2883 to ask for a copy.
The information offered in the pamphlet is excellent. That said, I no longer own an inboard boat, but if I did, I’d still leave its winterization to the pros.
The most expensive item aboard a boat is also the most vulnerable to Great Lakes’ off-season weather. Whether you do-it-yourself or pay someone else to do the job, boat insurance claims show that engine winterization mistakes can be made — and lead to the complete loss of the boat’s powerhouse.
While most boat insurance policies won't compensate the owner in such instances, as freeze damage is considered a maintenance issue, some do offer extra "freeze coverage" insurance to a boat's policy at an additional cost. It generally covers damage to the engine and a boat's systems as a result of freezing water. Freeze insurance may also be of interest to owners of boats who trailer their craft south for vacations or fishing trips over the winter, and return to the Great Lakes when freezing temperatures can still damage a boat or its engine.