Winter storage

By: Norman Holtzhausen, Photography by: Norman Holtzhausen

Winter storage Winter storage
Winter storage Dry stack storage at Oram’s Marine Village, Auckland Winter storage
Winter storage Prevent the metals coming into contact with each other by using nylon washers and bushes to insulate them Winter storage
Winter storage Note the Duralac around the stainless screws in this aluminium fitting Winter storage
Winter storage UV damage, heavy rain and a badly fitting cover can cause failure Winter storage

Not keen on fishing, diving or water skiing on these short, cold days? Well, if you want your pride and joy to be ready and able come spring, have a read of this…

Winter storage
The off season

After a splendid, long summer that everyone except the farmers enjoyed, winter has now arrived with a bang. When the temperature plummets, the temptation is to pack the boat away until Labour Weekend. The worst thing you can do, however, is to just throw a tarpaulin over it and tie it down tightly.

Fresh air is critical to prevent mould and rot setting in, especially if the interior is in any way damp. Without air circulation you could be up for extensive (and potentially expensive) repairs by the time spring comes around. A couple of hours' preparation and a few modest investments before putting the boat away will prevent many of the issues that could otherwise spoil your summer boating experience.

So let's look at the steps you should take in preparation for an extended period of non-use.

Wash everything thoroughly

Before packing the boat up you need to make absolutely sure there is no salt anywhere. Even a tiny amount can cause corrosion over an extended period. Any bait or fishy residues left on the boat will also develop into quite a pong if left too long, so you want to get rid of anything that could cause problems. You should spend more time on this wash than your usual post-trip clean up. Use a detergent or, better still, a salt-inhibiting product like Salt Away or similar. Wash the trailer and motor thoroughly as well, and don't forget to thoroughly rinse the trailer suspension and brakes.

Also check for lost sinkers and fish tackle in the bilges, under the seats or on parcel shelves. A rusty fishhook left for a few months can permanently stain a gelcoat or cause galvanic corrosion on an alloy hull.

The other reason for putting the boat away in a clean state is that moisture likes to condense around particles, so a dirty boat will have more moisture sitting on the surface than a sparkling clean one. A suitable boat wax (chosen appropriately for your boat type) is also a good idea to create a further barrier.

Make sure everything is dry before covering up

If the boat is wet inside before you start, sealing it off will simply trap that moisture in, so make sure everything is totally dry. Choose a nice sunny day for the clean up. Lift the carpets and squabs, and if possible store them in your garage or somewhere else that is completely moisture-free. Check the bilge is clean and dry and there's no water in any of the inner recesses. Open all cupboards and lockers so air can circulate.

For wooden boats especially, it is a good idea to install some sort of dehumidifier to prevent the dreaded dry rot. A simple and effective solution is Damprid, and a bucket of this can be stored (open) on the boat. As the crystals absorb moisture they eventually liquefy, and should be checked regularly and replaced when required.

Grease everything

Prep the trailer by checking the bearings are fully packed with grease, and also grease the jockey wheel and override break. If your trailer is braked, be sure to check the brake fluid reservoir is full and the cap seals properly. Any exposed metal surfaces should be given a light spray of something like Inox MX3 (which comes in a handy spray bottle), creating a barrier that helps prevent corrosion.

One area that rusts very quickly on a trailer is the disk brake surface. This cannot be galvanised or greased since it requires friction with the brake pads to work. You also don't want to put any Inox or CRC here, but a quick spray and rub-down with household furniture polish will give it some protection against rust. The first time you use the brakes again this will rub off.

Prep the engine and fuel

There are different approaches here depending on the age of your motor. At the very least you should consider having the motor serviced, and replace the oil in a four-stroke. Replacing the outboard or stern leg's lower gearbox oil is also a good idea, because any water or contaminants that have got into the oil could cause corrosion.

Modern engines do not require prepping, and in fact many manufacturers caution against it. However, if you have an older model then some preparation may save expensive grief. The basic idea is to get a thin film of oil into the cylinders, to coat the otherwise unprotected steel components. A light oil can be sprayed into the carburettor while the engine is running, or remove the sparkplugs and spray oil lightly into each cylinder before replacing the plugs.

The trim tilt mechanism, steering and associated hardware is a prime spot for corrosion when not in use, and a light spray of Inox MX3 over this whole area is also a good idea. Turn the steering so the full length of the shaft is exposed, then spray it before turning it the other way so the shaft is hidden back into its tube.

It is important not to leave a fuel tank partly empty. Both petrol and diesel have issues — diesel grows a bug when water gets in, and petrol destabilises in the presence of air. So the solution is to either drain the tank completely or to completely fill it. Once full, add a biocide to diesel or a fuel stabiliser to petrol.

Buy a good boat cover

Although a plastic tarpaulin from a hardware store is the cheapest option, it will not fit the boat properly. These tend to break down in the sun's UV rays, and may start to leak before you notice anything amiss. It will cost more, but buy a proper boat cover that fits.

A proper cover will fit tightly over the boat and force the water to run off. It should not allow water to pool anywhere, and should strap down tightly so it cannot flap in the wind. Check there are no flat or concave areas where water could sit, as ultimately this will cause the cover to leak or even rip.

Ensure there is airflow

Although the purpose of the boat cover is to keep water out, it is best if air can flow freely into the boat. Try and tie the cover so there are openings for air but not rain to get in. This will ensure the interior of the boat does not become mouldy and musty.


Any type of lead-acid battery is likely to deteriorate when left unused. Consider a solar-powered trickle charger (Cover Systems now offer boat covers with a built-in solar panel) to keep the charge topped up. Alternatively, take the batteries out and charge them every month or so.

Choosing a storage location

You may keep the boat in your back yard during the summer, but when the ground turns to bog it may be better to park it somewhere on a hard dry surface. Choosing a suitable storage facility requires a bit of research, based on your location, availability of space, price and facilities they have available.

Once you find who has available space, and their prices, go and inspect the facilities. Look for a place with 24/7 access — there are some fantastic days in winter, and you will want to be able to get your boat out at short notice.

The big names in storage all have multiple electric fences and security cameras, with 24/7 monitored alarms. Look for big open areas that are highly visible — a small yard tucked behind a factory unit could allow thieves plenty of undisturbed time to rip electronics and gear out of a boat, even if they don't take the boat itself.


If you are storing your boat away from your house (or even in your yard), consider some sort of tracking device or alarm. These may require you to leave a battery in the boat, but the new generation of devices can be set to send a text message to your mobile if the boat's location changes more than a few metres.

Don't ignore your boat all winter

One of the biggest mistakes made is to pack the boat away and then leave it for four or five months. During that time any issues, such as a leaky cover, can cause major problems if you don't sort them out.

At least once during the winter, or preferably once a month, inspect the boat. On a dry day, take the cover off and air everything. Turn the steering full lock-to-lock a couple of times — due to the fine tolerances it only needs a very tiny amount of rust to jam this up solid. Trim the motors up and down, check the battery condition. If you can, fit flush muffs and start the motors, running them for a few minutes so they can warm up. Do not turn the motors over without water running, though, since this could destroy your water pump impellors in seconds.


The big killer for boats is galvanic corrosion. This is especially so in aluminium hulls but can affect metal fittings in any boat.

Galvanic corrosion occurs when different types of metal are in contact in the presence of an electrolyte, and causes one of the metals to decay through ions moving from one to the other. Lead-acid batteries use the principle to produce power, and salt water acts as a perfectly good electrolyte. The metals only need to be slightly different — even different grades of stainless steel or different alloys of aluminium in contact with each other can start to corrode once salt water gets between them.

Galvanic corrosion commonly occurs under fittings, engine mountings, where bolts go through the hull or anywhere different metals are present. Even a ball sinker left unnoticed in the bilge can cause a perfectly round hole to corrode right through the hull. The corrosion is often unnoticed until the weakened metal suddenly gives way under stress.

Of course, quickly rinsing away any salt is the most important prevention mechanism, since it is the salt ions that enable this process. The use of products like Salt Away help in this regard. However, there are also two ways to permanently prevent this type of corrosion:

Preventing the ingress of an electrolyte into the joint space is the obvious solution, and a sealant that completely seals up the space is essential. Duralac is the leader in this field, with its anti-corrosive jointing compound being widely used in the industry. While not cheap, it is a wise investment whenever installing metal fittings into any type of boat.

Prevent the metals coming into contact with each other by using nylon washers and bushes to insulate them. Due to the lower strength of these materials, this is not practical for stress-bearing components like stays and rigging, but is feasible when attaching rails and electrical fittings, especially to aluminium boats. Most chandlers will have a range of suitable nylon insulators.

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