3rd Oct 2025
For many boat owners, winter is the time when your vessel comes ashore or is left on its mooring to face months of cold, damp, and inactivity. Preparing your boat properly for lay-up is crucial to protecting your investment, avoiding expensive springtime repairs, and ensuring a trouble-free start to the new season.
This guide covers everything you need to know - from engines to electrics, and interiors to covers, so your boat is in the best possible shape when you return in spring.
1. Planning Ahead.
Before lifting out or beginning your lay-up routine:
- Check your insurance policy – Many require certain lay-up measures, such as fuel tank precautions or battery disconnection.
- Create a checklist – Every boat is different. Note which systems you have (engine type, heating, electronics, etc.) and plan a sequence.
- Book services in advance – Yard services, antifouling, and shrink-wrapping fill up fast in autumn.
2. Hull & Exterior Care.
Hull Cleaning and Inspection:
- Pressure wash immediately after lift-out – antifouling paint hardens quickly once dry, making cleaning more difficult.
- Inspect the hull closely – Look for osmosis blisters, gelcoat cracks, or damage. Note repairs needed over winter.
- Remove anodes – Replace sacrificial anodes if more than 50% wasted. Check shafts and propellers for wear.
Antifouling Preparation:
- Scrape and sand loose paint – Winter is the best time to prepare for a fresh antifoul coat in spring.
- Check through-hull fittings and seacocks – Operate them, grease if necessary, and ensure they’re not seized.
Topsides and Deck:
- Wash and wax topsides - A protective polish prevents grime buildup and reduces UV damage.
- Clean and protect stainless steel - Apply a corrosion inhibitor or light oil film.
- Check deck fittings and stanchions - Tighten loose bolts and inspect for leaks.
3. Engine & Mechanical Systems.
Inboard Engines:
- Flush with fresh water – Run the engine with a fresh-water supply to clear salt and deposits.
- Change oil and filters – Old oil contains acids that corrode internals over winter. Replace fuel filters too.
- Drain cooling systems (if raw water) or fill with antifreeze solution for protection.
- Fog the engine – Spray fogging oil into air intakes to protect cylinders from corrosion.
- Check belts, hoses, and clamps – Replace any cracked or worn components.
Outboard Engines:
- Flush with fresh water – Run on muffs or in a tank.
- Drain carburettors – Prevents gumming. For fuel-injected, use a stabiliser instead.
- Change lower-unit gear oil – Look for signs of water contamination (milky colour).
- Grease all fittings – Apply protective oil spray to external surfaces.
Fuel System:
- Fill tanks fully (diesel) – Reduces condensation and microbial growth. Add biocide if storing long-term.
- Stabilise petrol – Use a fuel stabiliser; petrol degrades in as little as 3 months.
4. Electrical Systems & Batteries.
- Fully charge batteries before disconnecting.
- Remove and store in a dry place if possible – Batteries self-discharge less in warmth.
- If left aboard, isolate switches and use a trickle charger or solar panel.
- Clean terminals and apply petroleum jelly to prevent corrosion.
- Check wiring for chafe – Cold and damp worsen hidden electrical faults.
5. Plumbing & Fresh Water Systems.
- Drain all water tanks – Standing water stagnates, breeds bacteria, and can freeze.
- Run pumps dry to clear lines.
- Use non-toxic antifreeze in water systems, calorifiers, and heads. Pump it through until it emerges at outlets.
- Empty holding tanks before lay-up – Prevents unpleasant surprises in spring.
6. Interior Protection.
- Ventilation & Damp Prevention
- Remove soft furnishings if possible – Store at home in dry conditions.
- Use moisture traps or dehumidifiers – Helps prevent mildew and damp smells.
- Ventilate lockers and bilges – Leave locker doors ajar and floorboards lifted slightly.
Cleaning:
- Deep clean galley and fridge – Remove all perishable food.
- Clean bilges – A clean bilge prevents odours and corrosion.
- Wipe down all surfaces with mild cleaner or vinegar solution to deter mould.
7. Sails, Rigging & Canvas.
- Remove sails – Wash with fresh water and dry thoroughly before storage.
- Check stitching and UV covers – Arrange repairs before next season.
- Wash and dry covers, sprayhoods, and biminis – Store dry to avoid mildew.
- Inspect rigging – Look for frayed wires, corroded fittings, and hairline cracks around terminals.
8. Safety Equipment.
- Remove and service life jackets – Check gas cylinders and firing heads.
- Service life rafts, fire extinguishers, and EPIRBs if due.
- Check expiry dates on distress flares and replace as needed.
9. Covers & Storage.
- Invest in a good winter cover – Reduces UV damage, dirt, and water ingress.
- Avoid tarpaulins that trap moisture – Use breathable marine-grade covers where possible.
- Support covers properly – Prevent sagging and pooling water.
10. Final Checklist Before Walking Away.
- Boat secure in cradle or mooring.
- All seacocks closed (except cockpit drains if left afloat).
- Engine winterised and batteries safe.
- Water systems drained or antifreezed.
- Valuables removed.
- Covers fitted and secured.
- Regular inspection plan scheduled (every few weeks if possible).
Key Takeaway
Proper winter lay-up is less about one big task and more about attention to detail across every system. By investing time in careful preparation, you’ll protect your boat from winter’s worst effects – saving money, preventing corrosion and damp, and ensuring you’re ready for a smooth launch when the sun returns.
