18 Oct2016

Overwintering your boat

Winter care for engines and interiors

With the boat properly secured to the pontoon and the sails and covers prepared for winter winds, its time to turn to the interior. These are our suggestions for a stress-free lay-up afloat:

Interior of a yacht with the fridge lid propped open to ventilate during winter at East Cowes Marina

Clean and air the fridge

A through hull fitting seacock on a boat in the closed position at East Cowes Marina

Close all seacocks


  • Close all seacocks


  • Service and winterise the engine your self, or get an engineer to do it for you
  • Change engine and gearbox oil
  • Spray the engine with WD40
  • Add antifreeze to fresh water-cooled engines
  • Check the engine manual for specific advice


  • Fill tanks to reduce condensation
  • Add a suitable bactericide to prevent fuel bugs


  • Take batteries ashore for day boats and RIBs - most boat batteries are too heavy to move safely
  • Use a smart-charger to keep batteries charged
  • A galvanic isolator is a good idea when plugged-in to shore power


  • Drain-down fresh water systems to avoid frozen pipes splitting
  • Turn off all gas appliances and disconnect the bottle
  • Switch off fridges/freezers and leave the door/lid propped open to stop mould
  • Check all non-essential electricals are switched off to save power
  • Clean and drain the sea toilet - manufacturers often recommend descaling the bowl and pipes


  • Dry the bilges and leave floor boards propped up to allow air to circulate
  • Empty all lockers of food, books and clothing
  • If possible, take cushions and upholstery ashore. Otherwise lift cushions so they don't attract moisture


  • Dehumidifiers - use a proper marinised dehumidifier in a secure position. Dehumidifiers can cause fires, so please be very careful
  • Cool-touch tube heaters are safer and cheaper than oil-filled radiators or fan heaters
  • A low tech option for keeping the interior sweet is to take everything posisble home, to encourage indirect air movement through the boat, and to use moisture-attracting crystals instead of a dehumidifier
A yellow dehumidifier on a yacht at East Cowes Marina

Dehumidifier, your choice

Blue cushions inside a yacht set on end to air in the winter at East Cowes Marina

Cushions airing

A yacht diesel engine

Don't forget the engine

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