Screaming “I’m on a boat” is great if you don’t have to pay for it.

Boat ownership is expensive, and the costs go well beyond the down payment, maintenance and dock slip rentals. There’s also insurance and, as winter arrives, the cost of winterizing a boat that’s not going to be used for months.

If a boat isn’t prepared for winter and sustains freeze damage, a boat insurance policy may not cover the repairs. Just as car and home owners are expected to complete basic maintenance for their insurance to cover them, boat owners are also expected to perform basic maintenance, including winterizing a boat.

Even if you live in a coastal area with mild winters, this annual task can still save you thousands of dollars in repairs when boat season begins again. Boat insurance costs about $300 to $500 per year, depending on the size and type of boat, so this relatively inexpensive cost can save boaters a lot more money if something goes wrong.

Here are some ways to prepare your boat for winter:

Drain the engine: In a few minutes you should be able to empty water from the pumps and cooling chambers of the engine. Without this step, the freezing water can expand and the manifold and engine block can crack.

Flush the cooling system: If your boat has raw water cooling systems, flush the engine with fresh water to remove salt, dirt and corrosion. Anti-freeze can be run through the cooling system in extreme climate areas.

Fog the engine: Coat the inside of the engine with a protective film to prevent corrosion and rust. Spray the fogging oil through the air intakes while the engine is running. It will leave a protective chemical film over the internal engine surfaces. You can also spray a soft rag with the fogging oil to apply a light coat to the engine exterior.

Ready the fuel system: If gas is allowed to sit for a long time it can thicken and clog fuel injectors or ruin a fuel system. Adding a fuel stabilizer can prevent clogs. Also top off the fuel tank to avoid condensation build-up, and change the fuel filter.

Lubricate: Change the oil and the oil filter after the engine is slightly warmed up to help flush out sediment and impurities with the discarded oil. When draining the outdrive gear case, look for “milky” and discolored gear oil, which can be a sign of leaking seals.

Also lubricate small things that are lubricated regularly before the boat is stored for a long time. Apply a moisture-displacing lubricant to all moving metal parts, such as hinges, latches and ratchet mounts. Grease the trailer wheel bearings and remove the propeller to inspect for fishing line and shaft seal damage before coating the propeller shaft with grease.

Inspect everything: Look over the entire boat so you can catch small problems before they become big ones. Inspect mechanical steering and controls for worn cables, broken cable insulation or corrosion, and replace them if necessary. Check fuses and wiring connections, fuel lines, cooling hoses and hose clamps to make sure they’re not cracking, leaking or show signs of corrosion.

Dry and clean: Remove any standing water and clean up any dirt or oil on the boat, such as fish holds or storage areas. Remove all objects and clean the spaces thoroughly, adding commercial moisture absorbers to eliminate mould and mildew during the off-season. Clean all cushions and prop them up on edge for air to circulate.

Store your onboard stuff: Remove as much stuff from the boat so that it’s not subjected to the elements and doesn’t add to the gathering of dirt and moisture in your boat’s storage areas. Remove life jackets, dock lines, fire extinguishers, flares, ski ropes and other gear and store indoors. Also remove any electronics, such as radar displays and radios.

Winter storage: Keeping a boat in an enclosed, climate-controlled storage facility for the winter can cost $200 to $500.

If you’re going to store your boat outdoors, you can have it professionally shrink-wrapped to create a seal against the elements. Most people cover their boats themselves, with a custom-fitted cover the best option. Use supports to prop up the cover so that water doesn’t pool in low spots, and park the boat under a canopy or in a garage.

These are just some of the ways to winterize a boat. The boat and engine owner’s manuals can give more specific recommendations. You may need the help of your boat dealer or marine service engineer to perform the more complicated tasks.

Aaron Crowe is a freelance journalist who covers the insurance industry and specializes in personal finance writing.