With the winter drawing in, thoughts begin to turn to next summer’s boating – but it’s worth putting in some effort to make sure your boat makes it through the winter as best it can.

No matter what your boat, whether sail, power, narrowboat, speedboat, RIB or Jetski, there are things you can do to make sure it can withstand whatever winter throws at it.


If the boat is laid up ashore, you’ll need to winterise the engine by changing the oil, checking that the coolant is topped up or, in the case of raw-water cooled engines, flushing with fresh water before running some antifreeze through.

For boats left afloat in salt water, it’s unlikely that the temperatures will dip low enough to cause any salt water left in the engine to freeze, but it’s worth attending to if a particularly cold snap is forecast.

Make sure the fuel tank is topped up, which reduces the amount of condensation that can form in the tank and lead to diesel bug. Better still, add a fuel additive to kill and protect against diesel bug.

Water systems

Make sure you drain down all fresh-water systems on the boat to prevent them freezing, including water tanks and calorifiers. It’s also a good time to flush them through with a mild chlorine solution and rinse well to keep them clean and slime-free for next season. Leave your taps open to allow any water that does freeze to expand and escape without damaging the fittings.

For larger boats with outside water systems (for instance wash-down hoses and transom-mounted showers), it’s especially important to drain these down to avoid frost and ice damage.

Sails and Rigging

If your mast will be staying up, take headsails off their furlers and mainsails off the boom – they can be damaged by high winds and exposure to extreme weather. They also add unnecessary windage, which can be hazardous if the boat is stored ashore. Think about any sail repairs early in the winter, while the sailmakers are quiet – don’t leave it until the spring, when they will be snowed under with work.

If your mast is to come down, lubricate the rig’s bottlescrews to help the yard when they remove it, and take off wind instruments and VHF antennas to stop them being damaged. Coil halyards neatly at the base of the mast.

Down Below

If you won’t be using the boat, take cushions home if possible to keep them dry and mildew-free. If you have to leave them on board, prop them up on their side to allow air to circulate.

Wash out the bilges with detergent and fresh water and sponge it out again. This removes salt that will retain moisture and keep the inside of the boat damp all winter.

A dehumidifier will keep the interior fresh – but make sure it can drain overboard and is wired up via an RCD-protected supply to avoid fires. A greenhouse-style heater is another option, which will keep the temperature above freezing for minimal power usage.


Flush your seacocks through with fresh water and lubricate the moving parts to stop them seizing up over the winter.

Mooring lines

Don’t forget to check your insurance policy to ensure that you’re covered, whether the boat is hauled out ashore or still afloat. If the boat is on a pontoon, add extra fenders and lines, and consider adding rubber snubbers to the mooring lines if the boat is in an exposed berth.


Even if your mooring is a secure one, it’s worth taking any expensive electronic and navigational equipment home with you to store in a safe place.

A winter cover

Investing in a good winter cover will mean you will have much less work to do in the spring to bring the boat back into commission – she will be clean, dry and ready to go. Shrink wrapping is a one-use option, or you can get a custom-made cover that you’ll be able to use year after year.

Check you’re covered

And finally, don’t forget to review your insurance policy to make sure your boat and its equipment is covered, whether afloat or ashore.