Rupert Holmes looks at the key issues to consider when the time comes to prepare a boat for winter lay-up...


Many of us are lucky enough to be able to keep our boats afloat all year and can therefore sneak in some winter sails – or even short cruises – in periods of good weather. For others there’s no option but to haul ashore and prepare for winter. Whatever the reason, or time of year, laying up for a period out of the water requires a similar process.

Most boatyards, for example, insist that roller furling headsails are removed beforehand. This is a sensible policy given the carnage that could be wrought if the sail became unfurled during a gale. It’s also a good move to remove all other canvas work, including sail covers, sprayhoods and dodgers during any long lay-up, summer or winter.

In winter these gather dirt and mould, often at an alarming rate, while leaving them fitted for long periods in the summer will result in UV damage and consequent loss of strength. This is what I do with my boat in Greece – the sail cover still looks almost new after 20 years, as does the lifebuoy.

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Batteries will discharge at a rate of 2-3% per month if left unattended. If they weren’t fully charged on laying up this can result in significantly reduced charge that may cause problems when the time comes to launch. Keeping charge levels topped up while the boat is ashore will also help maximise their lifespan.

There are a number of ways to achieve this without going through the hassle of taking them home. If there’s a permanent shore power supply to the boat this can be connected to the type of battery charger that can be left on continuously. At the other end of the scale are very small boat solar panel – if their rating in watts is less than 10% of the battery capacity (measured in amp-hours) then they can be left permanently wired in without a charge controller.

This is the method I used until just over 10 years ago. It proved both reliable and cost effective, using 5-10W solar panels that cost around £10 each and could simply be laid on deck when the boat was out of commission. Today I use larger solar arrays that are permanently wired in via a regulator. This means I know the batteries are charged with the same regime when the boat is ashore, as when it’s in commission.


Small solar panels are a cost effective and reliable way to keep batteries topped up

Fill her up!

Diesel tanks should be topped up to prevent condensation adding water to the fuel, which can then prompt the growth of bacteria that may subsequently clog fuel filters. If possible it’s worth making time to check there’s no water already in the tank. Many are fitted with either a drain tap at the lowest corner, or an inspection access on top, which will allow a sample of the fuel to be taken.

If this the fuel is clear then you have no worries, but if it shows water or dark bacteria, then the problem will only get worse during layup and should be dealt with immediately. In an ideal world it would be possible to drain water tanks and leave them open to ventilate.

Unfortunately, that’s not always either possible or practical. Nevertheless, leaving old water to fester in them for an extended period is not recommended. Equally, if you want to prepare a boat for winter you’ll want to ensure water in pumps and so on won’t freeze.


The saloon of a well maintained Contessa 32 – keeping it dry over the winter, with good air circulation, will help to keep it in this condition

Given it’s almost impossible to empty water from all elements of the system, a sensible precaution is to flush though both hot and cold water systems with a propylene glycol-based antifreeze intended for drinking water systems.

Those who leave their boats afloat over the winter in southern England tend not to winterise engines, hoping instead that the combination of higher water temperatures and the salinity of sea water will protect against freezing. But it’s a different matter when hauling ashore, when raw water cooled diesel engines in particular are at risk if not winterised.

Traditionally the best time to service an engine was after laying up – that way there’s no old acidic oil sitting in the motor for months on end. This is less of a problem for modern oils, but the principle is still a good one as any problems found at this stage can be easily rectified before the spring and early summer rush. It also means the unit can be properly winterised at the same time.

Beat the damp

The biggest enemy to a boat’s interior is damp, which will cause mould to grow on surfaces including interior woodwork, which is unsightly and difficult to remove. It can also damage soft furnishings, especially bunk cushions, which are expensive to replace. If you have spare dry storage space it may be feasible to take cushions home before you prepare your boat for winter, but that’s not an option for many of us.

Instead, airflow is the key to keeping everything in good order. Stand cushions on edge and leave locker and cabin doors open. If it’s possible to safely and reliably run a boat dehumidifier, with the outlet draining into the galley sink, this will keep the interior dry. Otherwise, ventilation is the key to a dry boat.

Many are not set up to create a good airflow, so it may help to add extra vents to washboards or leave hatches cracked open if the yard has appropriate security. It’s also worth inspecting the rig before hauling ashore, including going aloft to look for anything amiss. If problems are discovered, with either standing or running rigging, at this stage they can easily be sorted in good time before the boat is launched.

The time to act on any big jobs is as early as possible in the autumn. Even if you intend to do the work yourself, the pandemic-induced surge in boating means some spares are difficult to source and have long lead times. And most marine suppliers revise prices in November, so buying early often means useful savings.

If you need professional help with any aspects of the work needed to prepare a boat for winter, then this is best booked as soon as possible. Even in normal times marine trades are very busy in spring and summer, so booking work in as early as possible during the autumn is a key to getting it done without impinging on next season’s sailing.


Attending to key items right away is the route to launch on time in the spring

How to prepare a boat for winter: Ken Endean’s checklist

As soon as our boat is launched I start to make entries in a dedicated notebook. It’s a list of everything that will require special maintenance during the winter lay-up period (i.e. excluding regular annual items such as antifouling).

It includes non-urgent repairs, desirable additions or changes, and any bright ideas for improvements and better sailing. For instance, this year’s winter lay-up list starts with a note to re-grind the heads inlet seacock, which has been dribbling water but cannot be fixed while afloat and will dry up as soon as the boat is ashore.

It may include cosmetic annoyances such as rusty anchor chain: after 10 years or so it will leave stains on the deck and will need replacing but I might forget about it while it is ashore and drying out in the chain locker.

Things like defective drawer catches will only be noticeable while at sea and well heeled. Last year’s list included disabling the swivels on two blocks to make their lines run more smoothly, without twisting.

If the ensign has flapped itself to death and needs replacing, that will be recorded, and the list will serve another useful function in December. If the family ask what Dad wants for Christmas, my wife can consult the notebook and a new ensign will be better than a pair of port-and-starboard socks.

The hull and openings

Any issues affecting the hull in water must be identified before the boat comes ashore, especially if that involves tracing or testing. If you think the stern gland might be leaking, inspect it while afloat and trace the leakage to make sure that diagnosis is correct.

On my dribbling seacock, in a damp corner, the minor seepage is difficult to study but I’ve taken trouble to eliminate the bolts and the hull seal, so re-grinding the cones becomes the most likely solution.

If a WC pump is playing up, its intake function will be difficult to test in the boatyard, so check it thoroughly while the inlet is submerged.

For owners whose boats have holding tanks, there’s another absolutely vital task that must be performed (not merely listed) before the boat comes ashore: flush the holding tank! If you try that in the boatyard you may become very unpopular!

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This feature appeared in the November 2021 edition of Practical Boat Owner. For more articles like this, including DIY, money-saving advice, great boat projects, expert tips and ways to improve your boat’s performance, take out a magazine subscription to Britain’s best-selling boating magazine.

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