Many costly narrowboat faults that occur as a result of bad weather can be avoided with a bit of forward planning. As part of your annual narrow boat maintenance, it is essential to build in a winterising plan.

Narrowboats need to be prepared for the winter
Winterising your narrow boat is important particularly if you leave your narrowboat over the winter
Winter months can be harsh on a narrowboat

Winter Preparation… What Do You Need To Know?

For the owners of caravans and static holiday homes, winterising is an essential part of the annual maintenance plan.

So it should be for narrow boat owners. In reality, it is a much overlooked task which every year, if neglected, leads to problems for many owners. Even those of us who live aboard will need to modify our use of our narrowboats and especially so if we are hooked up to comfortable marina power and don’t have the need to run our engines periodically.

The last couple of winters have been harsh. If we’ve not had deep snow and thick ice then we’ve had to contend with high water levels and flooding in many areas. Both environmental extremes can be damaging to our investments but there are steps we can take to minimise risk.

It is worth checking your insurance policy to ensure you are covered for frost damage as this isn’t standard on all policies. If you are covered, insurance policies normally insist ‘machinery is winterised according to manufacturers’ recommendations.

Take time from your schedule to plan these tasks before the weather sets in. Those of you who have to travel distance to your mooring will have a bit more thinking to do when arranging the tasks but a bit of time here can save a whole heap of grief at the start of the new season. If you are a member of a syndicate, check that winterising is done as part of your plan. At the very least try to have someone close to the mooring take responsibility for regular checks during any particularly bad weather. This may be a live-aboard neighbour or the marina staff.

We can split the winter tasks into easy chunks:

Ropes, Fenders & Cruising Hardware

If the narrowboat is laid up over winter and you have storage facilities then consider removing ropes, fenders, poles & hooks etc. Try and get hold of a second, serviceable, set of front and rear mooring ropes and maybe attach an old centre rope for “just in case”.

Fenders and ropes are expensive to replace and bad weather will break them down, causing rotting or degradation to chains and shackles.

Wooden poles and planks will likewise be affected by bad weather so stick them in the garage or store them away from the elements. You could even give them a coat of varnish or oil if you get bored on those long dark nights.

Exterior Paintwork, Covers and Windows

Give it a good coating of wax. Get all the sap off the paintwork and maybe even do a light cutting back of the paintwork before applying the wax. Any protection you can give to the topsides is worth it with paint jobs costing over £100/ft from the professionals.  Treat any rust spots with a treatment chemical before touching up the paintwork with your spare paints.

Incidentally, there are paint mixing companies who will mix you up a litre of paint for a very reasonable price if you know the BS or RAL number of your paint colour. Most chandlers will sell good quality enamel paints suitable for marine applications and are more than happy to advise on rust prevention.

If you can, visit the narrow boat regularly and keep deck drains free from blockage by spiders webs and leaves. Treat cratch, tonneau and side hatch covers with specialist vinyl cleaners which help to protect the fabric. Touch in any scrapes that the years cruising has inflicted on the sides, gunwales and rubbing strakes. It’s easier to roll on a bit of blacking in the Autumn than to deal with flaking and deep rust in the Spring.

Whilst you’re messing about topsides, pop on the chimney cap & check the seal on chimney collars and any other potential inlets. If necessary, use that tube of marine silicon you’ve got in the spares kit to quickly run a seal around these areas. Don’t underestimate capillary action. It is very difficult to spot initially but can do immense damage to interior panel work so carefully check around the windows whilst you’ve got the sealant gun out.

Engine & Associated Systems

As we mentioned in the servicing introduction, it’s good practise to change the oil and filters before laying the narrow boat up for winter. Fresh oil is much kinder to the engine as old oil contains highly corrosive byproducts of combustion. Any water that may have collected over the summer can be removed from the diesel filters as a result of the renewal.

Fill up the diesel tanks? It is a fact that condensation can form on the inside of a partially empty tank. The water then settles in the bottom of the tank and can promote the growth of diesel bug. Excessive water in the diesel will also cause the engine to run poorly with high levels of smoke. By filling up the tank, there is less chance of condensation forming. Alternatively, you could leave the tank level where it is and siphon off the bottom few litres of fuel in the spring thus removing any settled contaminant from the bottom of the tank.

The fuel does change from summer diesel to winter diesel during the months of November to March here in the UK. A standard known as the Cold Filter Plugging Point or CFPP is changed between the two seasonal products. This is the temperature at which the fuel will still pass through a filtering device. The cloud point of the two products is also different. Diesel is prone to “waxing”. As the temperatures get lower the fuel starts to crystallise. Summer fuel does this at 3’c and winter fuel can go down to -5’c before it occurs. Ask your supplier what they recommend for your specific circumstances.

At the very least, ask for FAME free diesel which has less water than biodiesel and therefore reduces the possibility of bacterial growth due to the diesel sitting unused for months in extreme weather.

Add a double dose slug of diesel fuel conditioner to the tank. This will help combat moisture and the growth of water related bacteria.

Check the operation of all bilge pumps. Consider the fitting of an automatic unit if you cannot visit the boat regularly. At the same time turn down the stern gland greaser and stop the dripping from the prop shaft.

If possible, keep the batteries connected to a smart charger. It is better to keep lead acid batteries topped up with a float charge than to let them discharge. If you have no mains power to the boat and live away, then take unused batteries with you, buy a good quality 3 stage charger and keep them topped up in your garage. Do not disconnect the battery that powers the bilge pump, instead rotate the battery when you next visit. Keep the batteries topped up if they are of the wet cell type and remove any corrosion from the terminals.

Ensure that the engine coolant is topped up and within date. Standard products will start to loose their anti-freeze abilities with age, usually at around 2 years.

For those engines that rely on raw water cooling, isolate the pump, clean the mud-box and drain down the water in the system. After draining down the water system (including drinking water and cistern), leave taps in the open position, this reduces pressure on the pipes if they do freeze over the winter. Lag any hot and cold pipes to protect them as far as possible.

Finally give the electrical components and connections a light spray of WD40 or similar to keep moisture at bay.


Remove any soft furnishings such as cushions or mattresses. If this is not practical, stand then up so air can circulate and prevent them from going mouldy. Check that all the vents are open to allow air circulation. If you have access to the cabin bilge, remove the cover.

Drain down potable water systems. Components that are particularly susceptible to frost damage are container type filters on drinking water pipes and the mesh filter bowl usually fitted to the water pump. If full draining is not practical, isolate the water tank at the gate valve, turn off the pump, open the taps and leave them open. Take off the shower head and leave the thermostatic mixer tap open.

Drain the calorifier and any rigid pipework if possible. If not, try and insulate the water tank with a temporary insulating blanket.

And Finally

Don’t be dismayed by what seems to be a lot of work. It’s not and it could save you hundreds of pounds in the short term. We’ve seen water damage from leaking windows & met owners who have lost calorifiers to frost action.

Cracked engine blocks from frozen water expansion do occur as there is usually only 6mm or so of steel from the frozen surface of the cut and your engine cooling skin tank.

Arrange to visit the narrowboat regularly or to have a responsible person do a regular visual check for you. If your boat is encased in ice, don’t rush to break the ice unless you have to move the boat as it can be very damaging to the hull of your boat.

Water can rise, even on the inland canals, so be aware of the weather in relation to your moorings and ensure ropes are of the correct length and are secure.

Let’s not be seeing a picture of your canal boat sat in the farmers field next February!

Winter Preparation

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