Laying Up for the Winter

Laying Up for the Winter. What is most important when prepping for the winter can be summed up by conditions. If it is going to freeze, winterizing the engine and any systems that have water in them, is the absolute minimum you will need to do. Any trace of water can cause havoc whether in an engine, toilet, bilge, outboard, air conditioning or running water systems.

If you have the space it is recommended that you remove as much ancillary gear from the boat. This stops the gear from getting cold damp and helps air move around the boat. It also stops certain items getting stolen. Check your insurance policy.

If you are having the boat pulled for the winter, most of the winterizing can be done in the water. The engine may be needed to get to the lift so that can be done onshore and engine mechanics have the tools to winterize on land.

Lowes Antifreeze -50 Degrees F
Lowes Antifreeze -50 Degrees F


Below is a fairly comprehensive list of projects that will help you in the spring. These are fairly general projects. If you are unsure about a particular system you should consult an expert at your boatyard.


Marine antifreeze comes in three different temperatures, -50, -60 and -100. At these temperatures the antifreeze will solidify. Glycol content increases from 30% for -50 to 60% for -100.

Propylene Glycol is more environmentally friendly. Do not use automotive type antifreeze, as they are toxic.

Boat System Winterization

Inboard Engine

The main goal with winterizing an engine is to remove any water from the cooling system and replace with antifreeze. The second goal is to service the engine.

If you have had engine issues during the season now is the time to take care of them. Mechanics have time to do work over the winter, and if you wait till the spring you will run into the spring rush, and hence delays.

Winterize & Service engine If you service the engine in the fall you will have fresh oil coating the engine & filters with corrosion inhibitors.

If you plan on winterizing yourself The list below is for DIY

  • Antifreeze type Use a -60 or -100 antifreeze for the engine. Any water in the cooling loop dilutes the glycol content. The -60 and -100 also have more corrosion inhibitors protecting the engine.
  • Antifreeze engine raw water Close the seacock if you are in the water! Remove the engine intake hose from the seacock. Put the hose into a 5 gallon jug of antifreeze. Run the engine to pull the antifreeze through the cooling system. Watch for it to come out of the exhaust and stop the engine.
  • Antifreeze engine fresh water In addition to above; Start engine and bring up to temperature. carefully remove the radiator cap on expansion tank. Check the antifreeze. If the antifreeze is old or dirty, it should be completely drained and replaced with the proper antifreeze and water mixture.
  • Raw water impellor Remover impellor, helps impellor survive down time.
  • Fuel filters Drain and clean all fuel filters and change elements, gaskets and seals
  • Change engine oil
  • Warm up the engine, which warms up the oil and opens up the thermostat. Once the oil has warmed up, turn off engine and change both the oil and the oil filter. You can use a hand pump like the picture below.
  • Change transmission oil Drain crankcase and transmission and refill with fresh oil as per engine specs
  • Sail drives Check & Change oil
  • Props Check the prop for damage. If the prop is damaged have it refinished. Check and grease prop & splines.
  • Geared props Folding feathering and geared props should be re-greased
  • Prop shaft Check cutlass bearing on shaft strut.
  • Packing Gland Check packing, replace if needed
  • Anode Replace shaft anode and prop anode
  • Exhaust Check hose for leaks, inspect loop

Outboard engines & Outdrives

  • Outdrives Most marine stores carry a winterizing kit (see picture below) that includes a plastic container for the antifreeze and a plastic hose used to connect to the flushing muff on the outdrive.
  • Outdrives Some I/Os and inboards will have separate cooling water intakes in the bottom of the boat. In these cases, remove the intake hose from the seacock and place it in a bucket of antifreeze.
  • Outdrives Inspect bellows for holes
  • Outdrive oil Drain and ad new outdrive oil
  • Outboard engine Outboards should be flushed with antifreeze, fogged, have the lower unit oil changed, greased and inspected. Four-cycle units need the crankcase oil changed.
  • Outboards storage Outboards are among items that are stolen, lock them up or take home. Store the engine upright.
  • Anodes Check anodes for wear, replace annually

Fuel tanks

Top off fuel tanks A full tank keeps condensation at bay. Water in fuel is disastrous. Fill tank 95% full.

Add Fuel stabilizer Add an appropriate amount of fuel storage conditioner to the tank. For E-10 fuel add a fuel stabilizer.

Stop water getting into tank. Make sure caps are tight and breather is not letting in water.


After winterizing cooing systems the next most important step is adequate ventilation.

If you do not adequately ventilate your boat, you will end up with mildew and a musty smell. Removing as much ancillary equipment as possible helps air flow which wards off mildew.

  • Remove anything you can; Cushions, sails, lines, safety gear, electronics can be taken home for dry storage.
  • Stop water getting below. Plug holes leaks that let in water
  • Dehumidifier A solar panel attached to a dehumidifier helps reduce moisture.
  • 12 Volt Dehumidifier Air Dry uses less amps than a 100 W bulb. Decide if you are leaving 12v operational. See shore power below.
  • Dehumidifier dry crystals Moisture absorb Dry crystals
  • Air circulation Dorade style vents will let in air but not rain or water.
  • Solar fan Deck vent with solar fan
  • Closing up a boat will lead to condensation You can use this approach with a good dehumidifier, otherwise you will have a damp boat.
  • Lift up Cushions Prevents damp getting between cushions and bunk boards.
  • Prop up Floorboards Lets air flow under floorboards.
  • MrGreen bilge cleaner and Kanberra gel can make your boat last without ending up musty and mold ridden

Onboard Systems

Winterize cooling systems with antifreeze

  • Generator Same as the main engine, winterize cooling system
  • AC System Pump Antifreeze into the AC cooling loop
  • Turn off stove Turn off gas @ bottle
  • Fridge freezer Remove food, open lid or door to vent

Water systems

All water systems should be run dry and filled with a antifreeze

  • Holding Tanks Pump out the holding tank. Leaving solids in the tank will lead to scale building up in the tank and pipes. Clean out with a biodegradable descaler or check your owners manual for recommendations. The descaler will break down solids and crystals.
  • Heads Flush your heads several times with fresh water. Ad a squirt of washing up liquid to help lubricate head and gaskets. Pump 30-50% antifreeze to the head and to the holding tank.
  • Holding Tank
  • After the descaling, Flush tank with antifreeze and fill discharge and intake hoses.
  • Vented loops Clean valve
  • Freshwater System:
  • Pump out as much of the fresh water as you can, you may have to open some pipes connections at the low points. Any water left in pipes can freeze or at best go stagnant.
  • Add antifreeze made for water systems Start with the faucet farthest from the pump and run it until the antifreeze comes out. Work your way back through the boat until antifreeze has appeared in all the faucets
  • Empty hot water heaters, Drain all water from heater, isolate tank from the system and add antifreeze
  • Shower sumps Any sea strainers you have should be sucked dry. If you can’t do that, add antifreeze.
  • Anchor washdown
  • Stern shower Stern Showers need to be winterized


If you pull the boat for the winter, this allows you to clean & service Seacocks.

  • Seacocks Open & Close Seacocks to make sure they work
  • Lubricate Seacocks Check which type you have and service requirements.
  • Clean any barnacles This can be done from under the boat. Barnacles restrict water flow.

Empty Bilge

Remove as much water from bilge as possible Add a little antifreeze to the sump. This will help prevent any water getting in over the winter, from freezing.

Electrical & Batteries

The decision here is whether you can hook up to shore power for the winter or are you going to add solar power for trickle charging or will you totally shut down the system.

  • Batteries Remove & store onshore in the dry. This is more important in very cold climates.
  • If you check your boat regularly, you can leave the boat Connect to shore power. But if you have a failure, you could loose your batteries.
  • Often when shore power is left on, so are batteries lights refrigeration. If you loose power your batteries will die, food go bad etc.
  • Clean battery terminals Lube terminals with Vaseline
  • A solar panel can keep batteries on a trickle charge. Snow can cover panel so beware.
  • Check navigation lights Nav lights get salt water corrosion, clean terminals

Electronics Systems

  • Remove Transducers Add the dummy plug
  • Remove any portable electronics Theft can be an issue
  • Cover on deck instrument displays

Deck gear

Wash away salt water. )

  • Remove sheets & loose lines, Wash lines with fresh water and dry before storing.
  • Remove Bimini canvas & Dodger canvas Wash with fresh water and dry. Fold carefully around windows
  • Hose down all fittings with fresh water. Loosen any salt buildup. Use this time to inspect all fittings. make a not of any fittings that need replacement or are suspect.
  • Cockpit drains; Make sure drains are clear.
  • Winches/Windlass Flush with fresh water, clean & service if necessary
  • UV light can damage compasses Make sure you ad compass cover
  • Windows ports Check for leaks
  • Check lifelines for wear

Sails & Rigging

Chafe is a big issue, sails getting loose, halyards banging. Remove all sails from mast, boom and furler if you have one. The next step is get some messenger line and pull the halyards. The will extend the life of the halyards and eliminate chafe.

  • Remove sails and wash with fresh water and dry. Take them to a sailmaker if they provide cleaning repair services.
  • In some Northerly parts its common to remove the mast. This is a good opportunity for a rig check
  • If you do not remove the mast, make sure chafe is not an issue
  • Halyards can be pulled with messenger line, or pulled to side with bungee to stop slapping
  • Roller Furler and main furlers
  • Flush furler drums with fresh water. Inspect locking nuts and check operation.
  • Halyards wash halyards with fresh water and dry before storing
  • Inspect all pins and turnbuckles Pull tape for inspection

Steering Systems

  • Check the rudder shaft packing gland Tighten packing gland if loose, should be hand tight.
  • Check steering cables & sheaves Tighten cables of they are loose
  • Hydraulic steering Check fluid level
  • Rack & Pinion steering Clean & grease sprockets as required The more you do now, the less you have to do in the spring.

Cleaning the Boat

  • Pressure wash antifouling Get a good bottom cleaner and clean the growth off the bottom now. This will make it much easier when it comes time to apply another coat of bottom paint
  • Prop Brush off barnacles
  • Clean any mold of canvas Clean and polish the clear vinyl.
  • Mildew Clean away any mildew now. It will get much worse over the winter

Finally; the more time you spend now will save hours in the spring. Also the spring is a busy time for engine mechanics and systems guys so if you have them serviced now you can be ready to go in the spring.