DirectoryServicesTech watchContact

clean + protect 


We recommend you read this whole section but you can choose to access specific information quickly by clicking on the links.

Engine Winterizing checklist

Exterior winterizing

Exterior winterizing checklist

Interior winterization



Printer friendly version

Winterization starts with a survey to be used as a checklist.  Use ours, use your own, or best of all develop a custom survey specific to your boat with a BoatCanDo checklist.  Divide your winterization efforts between the interior and the exterior of your boat.  Determine the coldest extended temperatures that may occur where you will store your vessel.  This will be the Freeze Protection Factor used to calculate anti-freeze ratios and heat/dehumidifier needs later in the winterization process. If you are unfamiliar with the idea of a Survey, then please read that section now.  This is also an excellent time to review your Boat Insurance particulars with winter lay-up concerns in mind.


An Important Note:  If you store your boat on a trailer, please make every effort to winterize your trailer before winterizing your boat and do so while the boat is off the trailer.

        Treating fuel

Hey_Chief would like boat owners to learn to think of their boats as a set of complimentary systems.  The boat’s mechanical and electrical systems are the most expensive, and therefore the most deserving of your close attention.  Certain systems will need to be winterized before the others.   I like to start with the Fuel System, because any fuel treatments you add to the tanks will then have more opportunities to get run completely through the fuel system and into the engine.  Ideally, one should treat their fuel year round, but if you choose not to do this, then try to dose the system on the last big trip of the season (for best mixing results).  Otherwise add the correct amount of treatment product to each fuel tank and top them off with fresh fuel at the end of the season.

Make your plan

At this time you need to decide what other types of projects you might want to undertake during the winter.  If you leave your boat in the water, and you are planning some boat projects or if you like to sit on your boat enjoying the harbor during the winter, consider delaying some of the winterizing steps if you need to run the engine for cabin heat or electrical power. You may choose to add an onboard marine heat system so you keep everything from freezing, this way your boat would always be ready to go. If you will not be using the engine during the off-season definitely winterize the engine and drive now.


Prepare by reviewing your vessel survey and run through your winterizing checklist mentally.  Collect the necessary tools, treatment chemicals, lubricants and filters.  Prepare the correct dilution of your Anti-freeze at this time. Switch to Propylene Glycol Anti-freeze now if you have not already done so. A lot of boats have a closed loop cooling system which holds either regular antifreeze or propylene glycol and a raw water system which brings in water from out side the boat. Both the closed loop coolant and the raw water coolant pass through the heat exchanger. This piece of equipment exchanges the heat from the closed loop system into the raw water coolant which carries it out of the boat. I recommend using propylene glycol in both systems as it’s safer for people, pets and wildlife, and with your help all boaters will benefit because you will be taking a positive step to preserve water quality now -- without being forced to do so by environmentalists in the future.

Cooling system prep

During the procedures which follow, you will be accomplishing several separate but complimentary winterizing tasks at the same time.  After treating your Fuel System, change all the zinc/anode plugs in your engine’s cooling system.  Change any coolant system filters now if you have them. Drain and replace the old antifreeze in the engine’s Closed Cooling System (if you have one).  Coolant treatments provide corrosion protection in addition to freeze protection.  Again, changing the coolant now is complimentary; it will be circulated throughout the Closed Cooling System as you complete the other winterizing tasks.

 Handy Tip

Consider installing permanent coolant flushing fittings in both your Closed Cooling System and your Raw Water System.  It makes service so much easier and you look much saltier than the ‘horn  who gets soaked struggling to get a good seal on the muff style flusher fittings.  Purchasing a packaged winterizing set-up like the Camco D.I.Y. Boat Winterizing Kit makes the winterizing task clean, easy and virtually fool proof.  Follow the manufacturer’s instructions.

Begin Winterizing

To begin winterizing the Raw Water System start by flushing that system with a Salt Removal Product like Saltex (they remove fresh water mineralization too!).  Follow the product’s instructions.  Next connect the garden hose to the winterizing kit and turn the hose on.  Confirm the engine is in neutral, and then start it up. Ensure coolant water flow.  Again, Hey_Chief repeats himself, “Confirm coolant flow!  And that’s an order!” Stop the engine immediately if you do not have coolant discharging normally.  Recheck your connections and make sure the hose is delivering water freely, and then start this procedure again and continue until water is discharging correctly. If you have only just added your fuel treatment and topped off your tanks, run engine about 10 minutes with regular water to make sure you have treated fuel all the way through the fuel system. At this point shut tap water off and switch to antifreeze mix. Continue running the engine until you see treated (pink) coolant being discharged.  The cooling system is now fully treated. Continue running the engine and spray the Fogging Oil in now.  If you choose not to fog, then you are done with the coolant flushing.  Turn off your engine’s ignition and disconnect the anti-freeze tank.


Fogging Oil cans come in two styles.  One is meant for engines with carburetors, the other for fuel injected engines.   Engines with carburetors can be fogged by removing the spark arrester/air cleaner unit and spraying the Fogging Oil directly into the carburetor while the engine is running.  Fuel injected engines can be treated by hooking the Fogging Oil can directly to a special port on the injection system while the engine is running.  Be sure to purchase the correct style can of Fogging Oil for your application.  Run the engine while spraying the Fogging Oil in until the engine runs roughly or stops.  Turn off the ignition.  Remove the spark plugs and spray a shot of Fogging Oil into each spark plug hole before replacing the plugs (check the spark gap!).  Turn the flywheel over by hand several times if you are able.

 Oil changes

Oil changes are the final steps in the engine winterizing process.  Do not skip these!  People mistakenly believe that their engines will be fine without an oil change.  Even if you “just” changed oil a few engine hours before, you must change it again.  If you do not change the oil now, the products of combustion in the dirty oil will form acids which will attack your bearings, cranks and other finely finished engine surfaces. Hey_Chief shivers with dread.  Engine service tech's laugh with avarice and glee.  Put on a new oil filter too!

Fuel and Air filters

Change all your fuel filters.  Bleed and prime the fuel system according to the engine manufacturer’s instructions.  Service your engine’s Air Filtration System too; replace all air filters and air blankets or wash and re-install the Walker AirSep units.

 Outdrives + Transmissions

Servicing your marine gear or outdrive is next.  This is very easy; just change the gear oil, wipe magnetic plugs clean and reinstall them with new gaskets, and install a new filter if your marine gear has one.  If you see metal shavings or chunks of metal (as apposed to fine metal dust) in the oil or filter, then have the drive checked by a service professional.  Some water droplets and even oil emulsified with water can be normal in an outdrive unit, but if there seems to be too much water, take a sample to an engine tech.  That’s it for your boat’s propulsion system.  Prop shaft bearings and stuffing boxes that accept grease or oil can be lubricated now.  The prop shaft itself can be wiped with a light coating of oil or other rust preventative.

 See you did it

You have now winterized your engine(s).So give yourself a pat on the back for a job well done.


 Engine Winterization Check List

Printer friendly version

1)Assemble Your Supplies.

 2)Add Fuel Stabilizer to all your fuel tanks.

 3)Replace all zinc/anode plugs in your engine’s cooling system.

 4)Change Anti-Freeze in Closed Cooling System with propylene glycol, change the filter if there is one.

 5)Flush the engine with Salt Remover while running Fuel Treatment into the engine.

 6)Flush the engine with Propylene Glycol Anti-Freeze at correct ratio until you see the treated coolant being discharged from the engine.

7)Spray Fogging Oil into the engine when you have about 1/3 of your anti freeze left in it's container. Start with small bursts of fogging oil then one long burst to stall engine as last of antifreeze is used. If it doesn't stall engine have someone switch it off now.

8)Turn off ignition and disconnect the flushing kit.

9)Spray Fogging Oil under each Spark Plug, and manually turn flywheel if possible.

10)Change engine lube oil and oil filter.

11)Change all fuel filters - Bleed and prime the fuel system.

12)Service air filter and air filter blanket if you have one.

13)Change marine gear or drive oil and service the filter/strainer if there is one.

14)Replace cleaned gear case plugs with new gaskets.



Printer friendly version

Start with the exterior of the boat.  Clean everything.  Hey Chief repeats himself: “Clean Everything!”  Now is the time to do all those little cleaning chores that have been put off during the busy (fun) season. This is actually the most time consuming part of winterization.  The boat must be put away clean; any dirt, biological grime, or petroleum products that are left soiling the boat will begin to permanently stain, corrode and ruin/reduce the value, security, and appearance of your boat!  When everything is clean, wax the hull, update any missing paint, and oil or varnish the bright work as needed.  Polish all metal surfaces with the correct polishing and preserving compound.  Now, refer back to the exterior checklist.

Use it to decide which items, if any need to be removed for winter storage.  If you are using any type of boat cover then you will need to remove all items that stick up above deck level. Downriggers, outriggers, pot davits, pulleys and rod holders or board/ski racks are all examples of things that should come off the boat.  Remove items that others might want to remove for you (theft), items that interfere with boat hull storage (convenience/cost savings), and any items that need to be removed from the boat to be serviced or repaired.

Now it’s time to clean your outdrive, outboard, or shaft and prop if the boat is out of the water.  Start by cleaning any marine growth off your propulsion gear.  If bare metal shows anywhere -- prime and paint it now.  Replace consumed zincs/anodes now too, even if the boat will be stored on the hard. Test and lubricate all your controls including; drive tilts, trim tabs, shift, throttle and steering cables.

Check all your tank vents.  They should be free (unobstructed and open) and they should all have some sort of cover.  Fuel tank vents must have legal and correct spark arrestors installed.  Water tank vents should be screened.  Examine all your through hull fittings including your exhaust system.  In some parts of the country it may be a good idea to temporarily cover or block through hulls and large diameter exhaust systems to keep vermin out (Important Note: Most Marine Insurance Policies DO NOT cover damage by vermin!!!).

Lubricate and inspect your deck equipment.  Grease winches, anchor windlasses and rollers.  If any of your deck equipment has gear oil-replace it now.  Check your running and standing rigging for wear or damage. If anything is supposed to swing, slide, or roll check that it moves easily before winter storage.

Safety equipment should be removed from the vessel.  Rodents and insects, unexpected impacts, and even the winter sun’s U.V. rays will degrade these important items.  Safety gear with USCG/SOLAS required maintenance dates should be sent to authorized service centers if their dates are expired.  Fire equipment on deck should be checked and removed for the season, BUT it is a good idea to leave the deck fire suppression equipment in place until all the other chores are done inside and out.

Cover the exhaust stack!!

This completes the exterior winterizing of your boat (except final covering etc.).  Consider shrink-wrapping your boat as an alternative to a cloth cover or tarps.


Exterior Winterization Check List

Printer friendly version

1)Assemble your supplies.

2)Clean the whole boat including the bottom, the topsides, and the propulsion gear.

3)Remove any equipment not meant to be stored on the boat for the winter.

4)Wax, paint, varnish, oil, polish and preserve all exterior surfaces as needed.

5)Replace hull zincs/anodes as needed.

6)Check and replace navigational lights and signals as needed.

7)Inspect and lubricate drive tilt machinery.

8)Replace all zincs/anodes on the drive now even if the boat is kept on a trailer.

9)Inspect and lubricate the control cables (steering, throttle, and shift).

10)Inspect and lubricate the trim tabs.

11)Inspect all rubber boots on the drives, control cables, and trim tabs.

12)Free all tank vents and ensure they have the proper style covers installed

13)Inspect and lubricate all deck equipment.

14)Inspect and lubricate all standing and running rigging (For sail boats).  Remove or stow the sails

15)Remove safety equipment for service and safe storage.

16)Inspect mooring systems including cleats, chocks, lines, chafe protection and fenders

17)Inspect your mooring slip or trailer bunks and rollers.

18)Winterize the dinghy.

19)Cover the exhaust stack!!!

20)Deploy vermin control devices

21)Tarp or cover the boat.

Interior Winterization

Printer friendly version

Gen Sets

        Auxiliary engines are winterized by following the same steps used to lay-up propulsion engines.  If your auxiliary is air-cooled, clean and service the radiator cooling system just as you would any other closed cooling system, and make sure the radiator screen and guards are clean, corrosion free and securely fastened in place. Follow the raw water winterization process, as described above, if your power system is cooled by raw water.

An Important Note:  When working on your onboard systems and their respective components remember; every special or specific set of recommendations the crew at BoatCanDo makes for you will mesh completely with the equipment’s manufacturer’s recommended maintenance procedures.  Do not skip any of their steps just because they are not explicitly mentioned here.

Hydraulic System

Hydraulic Systems do not need any particular winterization treatments-- just take care of them by following normally scheduled service intervals on the equipment.  If your boat has any sort of pressurized hydraulic receiver (tank) or emergency hydraulic starting pack then you may want to depressurize it for the duration of the winter.

If there are any grease fittings or as yet unmentioned oilers to be lubricated, do so at this time.  Lubricate the hinges to any engine room hatches, covers, and doors.


The winterization of the boats various plumbing systems can be fairly confusing.  Hey_Chief simplifies by separating out the parts.  Pre-existing drainage and service fittings really help in these situations.  If you would like help designing and installing custom service fittings just ask us for help at crew@boatcando <mailto:crew@boatcando>.  Your boat may have any or all of the three following systems: 1) Potable Water plumbing and tankage, 2) Marine Sanitation Device plumbing and tankage, and 3) cockpit or cabin drains.  

There are two basic directions basic directions to go with plumbing winterization.  One school of thought advocates complete drainage of the entire system and storage with all tanks, valves and pipes open and dry.  They other method infuses the system with an Anti-freeze solution much like the winterization of an engine.  Experience has shown that due to the complexity of modern plumbing systems and constraints imposed by the tiny spaces in which they are installed, it is best to combine the best of both methods.

Fresh/Potable Water Systems

If it is practical to drain your water storage tanks when the boat is not being used, then do so.  If you choose not to do this then treat the existing water in the tank with your favorite (you should already be purifying your water) water treatment chemicals but do not fill the tank above half full.  Add enough Propylene Glycol Anti-freeze to the tank to so that when it combines with the entire contents of the tank it will meet your calculated Freeze Protection Factor.  Freezing fresh water can apply fantastically destructive forces, so take care.

Here are some advantages to draining your tanks:

1) The hull is lighter; this is an advantage for both wet and dry storage.

2) There is a very low chance of bacteria and algae growth in the empty tank.

3) No possibility of burst damage because there is no water to freeze.

These are possible disadvantageous situations which may occur if you don’t drain your tanks:

1) Tanks or pipes may burst.  Then you may expect water damage to the cabin as the ice thaws next spring.

2) Bugs will turn your water tank into their own personal winter vacation spa.

3) Battering rams of ice may destroy your tanks, framing, and hull as you tow your boat on its trailer, or during any rough water conditions you may encounter.

(Ask the crew@boatcando <mailto:crew@boatcando> for a Sea Story now)

Electrical System

        Electrical system winterization and service is the cleanest and easiest project on the boat.  The winter lay-up is the ideal time to put a screwdriver to every electrical terminal you can locate inside your boat.  After you believe every connection has been tightened, then gently examine all heat shrinks, crimp connections, and wire nuts (Get rid of the wire nuts ASAP!).  Tighten again any electrical terminals that moved as you were examining the mechanical wire connections.  You may put a light coating of Dielectric Silicone on bus bar lugs and battery connections if they are clean and tight.

Inspect all your breakers and fuses.  Replace them as needed.  Tighten all conduit strain relief devices on the outsides of the boxes.  If your wire runs are clearly labeled; then move on to the next winterization section.

Batteries and their charging systems may be winterized by either of two methods.  The system can be fully decommissioned and the charged batteries removed to a cool storage location, or, leave the batteries in place and keep their condition maintained with an “intelligent” battery charger.  If the lay-up period is longer than sixty (60) days the batteries will want to be deeply discharged and then recharged normally for optimum Cycle Life.  Please email the CREW  if you would like us to provide you with a custom battery maintenance program.