Boat winterisation and end-of-season service
Quick answer
Winterisation is the service done at the end of the season so the boat survives the winter without damage: oil and filter change, fuel stabiliser and a full tank, cooling-system protection, batteries charged or disconnected, deep cleaning, interior ventilation and checks on hull, teak and mooring lines. It is usually done in October or November.
Why winterise at the end of the season
An idle boat suffers more than one in use: used oil is acidic and attacks the engine, diesel collects condensation water, batteries go flat and interior damp breeds mould. Proper winterisation prevents most problems when you restart in spring.
What the end-of-season service includes
- Engine: oil and filter change with the engine warm, impeller and anode check. See engine service.
- Fuel: full tank, stabiliser and water-separator drain.
- Cooling: clean raw-water strainer and protect the circuit.
- Batteries: fully charged, disconnected or on a maintainer.
- Hull and bottom: clean and decide on haul-out and antifouling.
- Deck and teak: clean and inspect caulking. See teak deck replacement.
- Interior: drain fresh water, clean bilges, ventilate and use moisture absorbers.
- Lines and fenders: double up for winter storms.
See the full plan in our boat maintenance calendar and the engine checklist.
Winterising afloat or ashore
In the Mediterranean many boats winter afloat. Then regular checks (bilges, batteries, lines) matter as much as the winterisation itself. If the boat is hauled out, it is the ideal time for antifouling, gelcoat and teak.
Frequently asked questions
When should a boat be winterised?
At the end of the season, usually October or November in the Mediterranean, before the boat sits unused for weeks.
Do I need to winterise if the boat stays in the water?
Yes. Even without frost, used oil, tank condensation, batteries and interior damp keep damaging an unprepared boat.
Winterisation & end of season by port
Winterisation & end of season: professionals by area
Related guides
Boat maintenance calendar: what to do each season
A simple annual plan to keep your boat ready: what to check before, during and after the season.
Boat engine maintenance checklist before the season
The list marine mechanics use to prepare an engine for the season, adapted for inboards and outboards.
Boat teak maintenance: a complete season-by-season guide
Cleaning, protection, caulking and sanding: everything a teak deck needs through the year to last for decades.
Other maintenance services
Engine service
Basic boat engine maintenance means changing oil and filters every 100–200 hours or once a year, replacing the raw-water pump impeller every 1–2 years, checking anodes, belts and coolant, and inspecting the fuel system. Doing it before the season prevents most breakdowns at sea.
View serviceAntifouling & haul-out
Antifouling is the paint applied below the waterline to stop algae, barnacles and other organisms sticking to the hull. In the Mediterranean it is usually renewed once a year during haul-out, when the bottom is also cleaned and anodes, propeller and through-hulls are checked.
View serviceBoat cleaning
Professional boat cleaning covers washing deck and hull with marine products, gentle teak cleaning without a pressure washer, rinsing stainless steel and cleaning interiors. The bottom can be cleaned in the water by a diver between haul-outs to keep performance up.
View service