Winterising top tips

RYA Sail and Motor Cruising Chief Instructor, Vaughan Marsh, shares his top tips for winterising your boat.

When putting your boat to bed for winter there are a few things to consider to help protect it throughout the colder months.

In simple terms, you need to either remove anything that could be damaged by freezing and damp or mitigate against that happening.

Boats contain a multitude of systems that hate inactivity, particularly the engine. Therefore, the best way to winterise your boat is to continue to use it. Whether you plan to keep using your boat during the colder months or to lay her up ashore, here are some helpful tips to winterise your boat.

Vessels left in the water

If you decide to leave your boat in the water ready for use, there’s potential for freezing and damp and you’ll need some form of protection. For those who’ll continue sailing this winter, we recommend the following:

Run the engine reasonably often, preferably in gear and while enjoying the quiet marinas and anchorages away from your home berth.
Use electric heaters with a thermostat set to above freezing both below deck and in the engine bay.
Set up a dehumidifier. Remember to drain it into the sink (not the tank).
Keep an eye on the power supply. This could be as simple as daily visits, or you could set up a monitoring system to alert you of low temperatures. A smart plug with a sim card can notify a mobile device of loss of power and can also be used to monitor temperature and even restart electrical devices.
Keep fuel tanks topped up.
Drain down the water from the external shower (if the vessel has one) and isolate it from the freshwater system.
Add extra mooring lines. Go to the vessel often and check and adjust them to change the potential chafe point.
Clean the outside of the vessel.
Tidy the inside of the vessel. To do this, start by removing any clothing and bedding. Consider emptying and deep cleaning your fridge, turn it off and leave the door slightly open to aerate it.
Check your hull fittings for leaks and corrosion.
Check your stern glands and repack with grease if appropriate. Note, there are many versions of stern gland so you will need to research this and ensure that you comply with manufacturer recommendations.

Vessels left ashore or not used

For those choosing to winterise their boats ashore many of the points above are still valid, but in we also advise the following:

Angle the bow slightly upwards to enable rainwater to run off immediately from covers, decks and cockpit.
Winterise your boat engine to protect it for the season ahead.
Covers should keep water out but allow air to circulate. Proper through-draught will prevent condensation which leads to dry rot, mould, and corrosion if left for more than a single season.
Look after the internal freshwater supply system. Drain the entire system including the tank, pump, calorifier, water filters and all taps especially shower mixers. Look for any areas where water could still be trapped in pipes. Plastic piping is less vulnerable than copper piping, but rigid unions can still be damaged by freezing.
Water-based central heating systems using antifreeze can be left alone provided they contain the correct water/antifreeze mixture. This can be checked using a strength tester available from marinas and good car spares outlets. Note that antifreeze has a limited life and if it has to be replaced then it’s a good time to replace any suspect hoses. Keep the old hoses as emergency replacements. If the system doesn’t use antifreeze, then it should be drained as for the freshwater supply.
Remove any food that could get damaged by the frost or attract unwanted ‘visitors’ such as mice and rats.
Store all linen, clothing, blankets, curtains etc. ashore – washed and dry. Prop the fridge door open, mould will form in less than a week if left closed. Ensure ventilation by leaving cupboards and drawers open, prop up bunk cushions and leave under-berth locker lids open. Get circulation into every possible conceivable nook and cranny.
Use tight fitting covers for deck-installed electronics and consider spraying behind electronics with water-repellent silicone. Check your navigation lights are still serviceable.
Make a list of what you have done to winterise the boat, so you remember what to reverse in the spring. Leave signs around the boat, so no one accidentally operates a winterised system.

Whether the vessel is lifted or left in the water it will still need frequent visits to ensure all is well. A weather eye still needs to be maintained and prior to any strong winds the vessel will need checking and securing.

Bilges will still need to be pumped, and any deck items checked for security and serviceability. If in the water extra lines may be needed, lines will need to be adjusted often to prevent chafe, fenders will need to be checked and adjusted and a check everywhere to ensure no unwanted guests have moved in for the winter.

Find out more

For further information on how to look after your boat this winter make sure to read our guide on winterising your engine.

To help prepare you for the season ahead find out how to get your boat ready for summer.