At the conclusion of the boating season, it’s not uncommon to winterize your boat to prevent any costly damage which may happen during the colder months from freezing, corrosion, dormancy and/or moisture.

For instance, if you fail to fog the cylinders with fogging oil, then rust may appear, whereas failing to flush the cooling system or even drain the gear oil case may lead to trapped water, which, when frozen, can expand and damage the expensive housing unit.  If you fail to drain the gear-case lubricant, for instance, it could lead to a $2,000 to 6,000 repair.

How much does it cost to winterize a boat?

The cost of winterizing a boat will depend on the professional you choose, the type of boat you have, the type of engine you have, the inclusions in the winterization and your geographical location.  From our research, as long as your boat is less than 40-feet long, the costs tend to be in the $400 to $700 range for a basic winterization services and often does not include any additional storage or shrink wrapping.  This seems to be the average price whether you hire a private mechanic, dealer or marina.

We were able to find multiple quotes people paid online and included our findings in the table below along with the source of the information:

Prices sourced online…
$450 for “full” winterization including oil change, outdrive lube replacement, etc.
$450~ quote for engine/drive/fresh water/toilet/AC systems including oil changes
$400 for advertised deal for ONLY labor. Needed to add the fluids, oil, filter and antifreeze
$680 for shrink wrap, fuel stabilizer and fogging oil
$560 for winterization and another $100 for the travel costs
$550 in Delaware for shrink wrap, mildew bags, oil change and stabilizer
$611 including winterizing the motor and heater, an oil change, impeller replacement and cleaning
$280 for oil change and winterization for 90HP Mercury 4 stroke

One dealer, for instance, that lists the prices they charge on the official website.  According to the pricing sheet, an outboard winterization, which includes a flush, fog, fuel conditioning, oil change, prop grease, fuel water separator change and anti-corrosion spray, can range anywhere from $290 to $375, depending on the horsepower.

Another Boat Storage, located in Counce, TN, offered a great checklist, showing you what each winterization option would cost.  For example, servicing and winterizing your inboard-outboard boat could cost $274, including tax, while winterizing but not changing the oil while doing so could bring the costs down to $219.

The extra costs

A lot of the times, if you want to store your boat outside during the colder months, then shrink wrapping will be a must.  This, unfortunately, will not be included in the costs above and can cost another $8 to $20+ per foot.

Storing your boat inside of a temperature-controlled facility can be another cost to consider, with the average storage fees ranging anywhere from $1,500 to $2,500 for the season or much less if you wanted the boat stored outside.

Pickup and delivery can potentially add hundreds, depending on how far the boat has to travel.  Most companies will charge a flat rate, often around $125 to $200, another $8+ per foot to haul and another $5+ per mile to travel.

The boat winterization process

A professional will first start by cleaning the boat and applying a rust inhibitor on all of the metal items and your steering/control cables.  He or she will also use what’s known as a “no damp” or some sort of mildew control bag and will apply it to any closed lockers and compartments.

Next, the fluid inside of the engine block, the manifolds, coolers and water pumps, all based on your engine specifications, will be drained.  The gearcase, at this time, will be drained and filled with a gearcase lubricant. Lastly, as part of the draining process, the porta-potty and fresh water system will be flushed, drained and a freshwater antifreeze will be added to the water tank.

After the drainage is complete, the fuel tank will be filled and stabilized with an additive while running the motor for about 15 to 20 minutes to make sure the additive reaches into the fuel lines.  Next, antifreeze will be pumped into the supply lines leading to the showers and sinks, followed by filling the manifold, block and the circulating pump with a propylene glycol antifreeze.  The cooling system and the lower drive of the sterndrive will then be backwashed in order to clear any rust flakes, salt and/or sediment out of the system.

Next, the fuel-water separator will be replaced, the oil and filter will be changed, and all hoses and belts will be inspected, just like a regular routine maintenance procedure to make sure everything is in working order.  At this time, the sterndrive gimbal bearing and engine’s coupler will be greased, followed by examining and lubricating the steering and trim.

At this time, he or she will then test the engine and use a fogging oil directly onto the cylinders until the engine stalls.  Doing can help prevent the parts from any corrosion during the colder months.

Following this, the professional will then examine the entire unit for any signs of rust and/or will repaint the entire lower unit as a precaution to prevent any rust.

In the end, the battery, all interior cushions, inflatables and jumpseats will be removed and stored inside of a dry, cool place.  All food, drinks and anything that could be ruined by moisture will be removed at this time as well.

When everything is said and done, the boat will be shrunk wrap if stored outside or will be wheeled into a temperature-controlled garage until it’s ready to hit the water again.  If the boat is stored on a trailer, then the wheels will be blocked and the tie down straps will be loosened to reduce any stress placed on the hull.

Tips to know

This helpful Popular Mechanics article shows you how to winterize a boat.