The preventable part
Why it matters
- Water left in an engine block, manifold, or outdrive expands when it freezes and splits cast iron. You will not find it until spring, and it is not repairable — it is a new engine.
- Untreated fuel breaks down over the winter. Ethanol pulls in moisture and gums carburetors and injectors.
- Batteries left connected discharge and freeze. Moisture trapped under a cover grows mold across the whole interior.
- Boats in storage are a target. Lower units, props, electronics, and trolling motors disappear from storage lots and driveways every winter.
From real claim patterns
What goes wrong over winter
Cracked engine block or manifold
Discovered at spring launch. Adjuster asks for the winterization receipt. If there is none, or the work was done by the owner without documentation, the claim is usually declined as freezing or lack of maintenance.
Cover or shrink wrap collapsed under snow
Water pooled, froze, and crushed the windshield, seats, and console. Sometimes covered, but often argued as a maintenance issue.
Mold and mildew throughout the interior
Almost never covered. It is a storage problem, not a sudden loss.
Theft from storage
Lower unit, prop, or electronics gone. Coverage depends on where the boat was stored and whether the policy was still in force — many people cancel for the winter and find out the hard way.
Plain-language orientation
Where coverage can change
These are common patterns, not a decision about your policy. Your carrier's form, endorsements, facts, and policy terms control.
Freeze damage to the engine or drive
Depends on your policy & stepsTypically excluded unless the boat was winterized according to the manufacturer's specifications — and many carriers want that done by a qualified marine shop with a receipt. Keep the paperwork.
Fire, theft, vandalism, storm, and falling objects
Often coveredCovered while the policy is in force. This is why we recommend keeping the policy active through the winter rather than cancelling it.
Wear, tear, corrosion, mold, and gradual deterioration
Usually not coveredExcluded on virtually every watercraft form.
Lay-up period
Depends on your policy & stepsSome policies include a lay-up period (for example, November 1 to April 1) during which the boat must be out of the water and not operated. Using the boat during that window can void coverage for the loss.
Reduced to storage or lay-up coverage
Depends on your policy & stepsIf you reduce coverage for the winter, call us before the boat goes back in the water or on the road. Liability and navigation coverage do not turn themselves back on.
Storage location
Depends on your policy & stepsYour policy may list where the boat is stored. Moving it from a marina to a barn, or vice versa, is worth a phone call.
Trailer
Depends on your policy & stepsOften covered under the boat policy, but sometimes only for physical damage and not while it is on the road. Ask.
Work in this order
How to put it away properly
Fuel system
Fill the tank to about 90% to limit condensation, add a marine fuel stabilizer, and run the engine long enough to move treated fuel through the whole system.
Engine and drive
Change the oil and filter while the engine is warm. Drain all water from the block, manifolds, and cooling system, then run marine antifreeze through it. Fog the cylinders. Drain and refill the lower unit gear lube (milky lube means a seal problem — fix it now). Check the impeller. If you are not confident in every one of these steps, pay a marine shop and keep the receipt.
Batteries and electronics
Disconnect and remove batteries; store them on a trickle charger somewhere that will not freeze. Remove GPS units, fish finders, radios, and anything else that can walk off.
Water systems
Drain and antifreeze the freshwater system, livewells, baitwells, bilge, and washdown pumps. Pump out and treat the holding tank.
Interior
Clean everything, dry it completely, and leave lockers and hatches open. Remove cushions and canvas if you can store them indoors. Place moisture absorbers in the cabin.
Cover and support
Shrink wrap or a proper fitted cover with vents. A tarp traps moisture and sags under snow. Support the cover so snow sheds. On the trailer, take weight off the tires with jack stands and check tire pressure and bearings.
Security and records
Lock the outboard or outdrive, lock the trailer hitch, and photograph the boat, engine, and HIN plate. Note the storage address and tell us if it changed.
Save as you go
Your winter checklist
Before you close the door
Tell us about long vacancies, storage-address changes, lay-up periods, and any vehicle or watercraft without its own active policy. If coverage is reduced for storage, call before the first spring drive, ride, or launch.
This guide is general information, not a coverage decision. Every policy is different. Ask us to review your own policy before a loss.