Winter Layup for South Australian Boats

South Australian boating does not really stop for winter, but it does thin out. Between about May and September a lot of boats sit — on the mooring, on the trailer beside the shed, under a cover in the yard. And more marine engines are damaged by sitting still than by being used.

What actually goes wrong over winter

Nothing dramatic. Four slow processes, all of which are cheap to prevent and irritating to fix:

• Condensation. Warm days and cold nights put moisture inside fuel tanks, engine oil and gearboxes. Water in oil is what turns a lay-up into a repair.
• Fuel going off. Petrol degrades in storage, and ethanol blends can absorb water. Stale fuel is behind a large share of the "it ran fine when I put it away" calls in spring.
• Rubber taking a set. Impellers sit bent in their housings, bellows and hoses harden, and none of it is helped by months of stillness.
• Batteries self-discharging. A flat lead-acid battery left flat sulphates, and sulphation is permanent. This is the most common thing owners replace in spring, and the most avoidable.

The lay-up list

Change the oil before storage, not after. This is the one people get backwards. Used oil carries acids and moisture from combustion, and leaving it in the sump for five months means five months of that sitting against bearings. Fresh oil and a fresh filter, then run the engine briefly to circulate it. The same logic applies to gearbox and drive oil — and drive oil that comes out milky is telling you a seal has failed, which is far better learnt in May than in October. Oils and filters for the Volvo Penta range are in the oil and lubrication range.

Deal with the fuel. The usual advice is to store a petrol tank nearly full with stabiliser added, so there is less air space for condensation, and to run the engine long enough afterwards that treated fuel reaches the carburettors or injectors. Diesel wants a full tank too, since diesel bug thrives at the fuel and water interface. Drain any water separator before it sits.

Flush and drain the cooling system. Flush salt water out thoroughly. If there is any chance of the engine being exposed to a genuine frost — more of an issue for inland and higher-country storage than for coastal Yorke Peninsula — make sure raw-water passages are drained or protected to the manual's instructions.

Take the batteries seriously. Either put them on a maintenance charger or take them out and charge them monthly. Clean the terminals before storage rather than after. If a battery is already tired going into winter, it will not be better in spring — our guide to choosing a marine battery covers picking the right replacement.

Grease, cover, and let it breathe. Grease the steering and control linkages, and the trailer's moving parts. Cover the boat, but ventilate it — a sealed cover traps moisture and grows mould better than it prevents anything. Leave lockers and the engine hatch cracked open where you can.

Store an outboard upright so water drains out of the leg rather than sitting in the cooling passages.

Boats that stay in the water

A moored boat has a different winter. It is not sitting dry — it is fouling. Growth slows in the colder months but does not stop, and the layup period is the natural window for antifouling, because the boat is not being used and it goes back in fresh just as the growth season starts. That timing argument is set out in our guide to antifoul work, and it is the busiest reason our slipway bookings fill from late winter.

Check bilge pumps and their float switches, and check the battery that feeds them, because that is the system doing the work while nobody is aboard. And keep the anodes in mind — they carry on being consumed all winter whether the boat moves or not.

Coming out of storage

Spring is not just turning the key. Before the first trip: check the oil for any sign of water, look at the impeller rather than assuming it survived, check fuel for water and the filters for anything nasty, test the batteries under load rather than trusting a resting voltage, and give every hose and clamp a squeeze. A tired impeller that sat bent all winter is a classic first-trip overheat — the reasoning is in our guide to when to replace an impeller.

The busiest weeks of our year are the first warm weekends, when everybody discovers at once what winter did. Booking a pre-season service in late winter gets the boat looked at before the queue forms — we do that across outboards and inboards through outboard servicing and repairs. Ring 0412 532 984 and we will get it in while there is still time to fix anything we find.