Seasonal Narrowboat Maintenance- winterising your narrowboat – and de-winterising in Spring!

We’ve tips on how to winterise your narrowboat when your boat is being laid up for the winter to avoid costly repair bills, and how to de-winterise your boat when Spring arrives. If you live aboard additional attention should be given to topping up antifreeze in keel cooling and other sealed water systems (such as radiators connected to the boiler) and making sure your hot and cold water pipes are well lagged and your heating systems work well.

Engine and transmission

Air cooled engines will not suffer ice problems, however water cooled ones will if not properly treated. Ensure the right amount of anti-freeze is in the water cooling system (if closed or keel cooling). If you have a raw water system, seal off the cock valve and if the engine is not to be used, drain the water out of the cooling jacket.

Winter on the canal

To keep water out of the engine and gear casing, fill the diesel tank to prevent condensation and add the correct ratio of fuel conditioner (available from most chandleries). Used regularly, fuel conditioner increases performance, reduces emissions and improves fuel economy. It also removes water from fuel lines and tanks, prevents and dissolves fungal growth, dissolves deposits from the fuel system, injectors and carburettors and de-carbonises combustion chambers. If you’re nervous about leaving a full tank of diesel idle over the winter, as it may be a tempting target for thieves, ensure your engine has a water filter – this’ll keep water out of the fuel line.

Grease the stern tube before leaving the boat, this will prevent water ingress. Although most stern glands leak once the propeller turns, the grease acts like a seal whilst not in use. Water in a boat will cause it to be lower in the water, placing outlets such as those for a shower, sink or air vent, nearer to the water level (leading to catastrophic results!).

Spray terminals with a silicone-free lubricant and grease all available grease points on the engine and drive, plus electrical connectors. Also lubricate linkages and gear/throttle slides, this will prevent rusting/corrosion and give these components a longer life.

General checks

Check lockers, cockpit and other areas to ensure all drain holes and plugs are clear of debris, leaves, dirt etc. These areas block easily and in heavy or prolonged rain, can cause a vessel to take on water causing corrosion where the water’s left sitting or even worse, sinking.

Always test the bilge pump and if possible, invest in an automatic one – it’s far more reliable than a manual.

Many of the sunken vessels attended over the summer would still be afloat if they had an automatic pump fitted. An automatic bilge pump immediately responds to water ingress with the float switch dictating when it should pump. Should a leak develop from cooling system, hull or other source (or there’s a build up of rain water), this will keep your vessel safe.

Make Regular Visits

Don’t just leave your boat to fend for itself through the winter! Visit the boat regularly, especially after heavy rain, snow or gales, to adjust mooring ropes, look for leaks and check bilge pumps and batteries are coping with the situation.

Regular checks to ensure batteries are charged are vital. Test the battery charge levels before leaving the boat. Heavy rainfall, leaking stern glands and issues with weed hatches can result in water ingress that quickly fills the boat and causes it to sink. If batteries go flat at a critical point it can be devastating.

It’s also a good idea to run the engine for an hour every time you visit as this pushes oil around the engine and prevents rusting, plus it tops up the battery if left running long enough (beware of doing this if you’ve drained the cooling system!).

Condensation and slight leaks around windows etc. can build up over the winter months creating mold and damaging panelling, internal finishes and fixtures.

Make sure there is adequate through ventilation and check regularly for leaks. This is especially important if your boat has a wooden cabin and/or hull!

Ensure boat mooring pins and ropes are secure, yet slack enough to deal with the normal rise or fall of water levels. Where possible attach a long rope to a tree or higher ground, so that if flooding occurs, or the boat becomes loose in high winds, the additional rope could provide a much-needed safety line.

To reduce discolouration, you may want to put grease on your external brass.


If not in use, store in a gas-tight locker – the same regulations as Liquid Petroleum Gas (LPG) apply here.

Water and heating

Burst water pipes can be a nightmare – yet easily avoided with some simple precautions; Lag your hot and cold pipes and top up anti-freeze in keel cooling and other sealed heating systems (such as radiators connected to the boiler). This point is being repeated because it’s the single most important thing to do, whether your narrowboat is being used over the winter period or not. Drain down the water system (including drinking water and cistern) and leave taps in the open position. Most water heaters have a screw plug at their base and most can accommodate an old-fashioned cycle pump which makes the emptying of water that much quicker. Taps should be left open because if any water is left in the system and it freezes, the pressure on the pipes will be less due to air coming out of the taps.

There’s also a pink anti-freeze on the market which is non-toxic and ideal if you don’t want to winterise your system.  You simply empty the water tank, pour the pink anti-freeze in, fill up the empty bottle with water and pour this in too and then run the water until it empties out pink from the tap furthest away from the pump.  Switch off the water and open all the taps.

Protecting possessions

Remove valuable items such as electricals, the television, even booze. If you have the luxury of a secure mooring this might not be such an issue, but if in doubt – take it out. Invest in a decent lock – the chances are this will deter a thief and your insurance policy requires this. There are alarms on the market that generate a text to your mobile if activated, however, the general consensus appears they are costly and have limited effect.

Mushroom vents are becoming increasing popular amongst thieves so check your covers for water/gas heater exhausts or air ventilators have a bar across the bottom of their thread – this ensures they’re difficult to screw out.

Deter solar panel pilferers by using a marine-grade UV bonding compound that sets in 24 hours and is rock solid. Use it for the panels themselves or to glue the feet of mounting kits that house glass panels– a less intrusive option than welding or drilling holes. Flexible panels can also be screwed onto a flat surface or clipped onto a narrowboat. Rather than using conventional nuts with bolts, use security shear nuts, whereby the nut is tightened to a certain torque and then the top section twists off leaving a tamper-proof cone. If you have glass panels, they’re more at risk of vandalism than plastic ones. There’s much debate over whether adhesive or shear nuts are the best option for securing solar panels. If you use marine-grade adhesive on the panel itself and not the mounting feet, it will be difficult to maintain the roof below and once stuck down, the panel is there for life, making it difficult to repair or replace. Shear nuts, however, can be removed with a fair bit of effort.

Don’t forget to put away any spare ropes and outside items such as boat shafts and gangplanks.

Our thanks to River Canal Rescue for permission to use this information.

De-winterising in Spring

Having gone through the process of ensuring your narrowboat can withstand sub-zero temperatures without too many mishaps, it’s worth noting you’ll have to do the reverse when warmer weather arrives.

This means turning the taps off, replacing the plug in the water heater and switching the water pump on. Once the water pump is back on, go to each tap in turn and run water through it. Start with the taps closest to the pump and work your way through to the one furthest away – this’ll push out any air locks. Drain any water in the tank out and refill before drinking.

And remember servicing, including the engine, LPG and electrical systems, plus fire extinguishers and escape hatches. All should pass Boat Safety Scheme scrutiny.

Although no action is needed for the gas pipes at the start of the winter, it’s a good idea to now paint connections with 50% soap liquid and 50% water using a small artist’s brush – this will show up any minor gas leaks at the joints.

In many cases damage arises as a result of something that has simply been overlooked and left to cause greater problems. For example, fire loss claims due to faulty gas fittings, issues with inverters/generators and claims for boat sinkings due to weed hatches being incorrectly refitted after cleaning, allowing water to seep back into the craft.

All materials and images © Canal Junction Ltd. Dalton House, 35 Chester St, Wrexham LL13 8AH. No unauthorised reproduction.

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