Wintering a yacht part 1/4: water, land or a hangar?

The end of the season is for most yacht owners a moment when the less pleasant topic of wintering arises. It’s a shame, because it is precisely these few autumn tasks that determine whether we will immediately dive into the season in spring or spend the first warm weeks repairing a cracked engine block, replacing flooded electronics, or removing mold from the entire interior. The cost of proper wintering is usually a fraction of the cost of the damage it prevents.

In this article — the first of a four-part series — we will address three matters that need to be established as early as possible: where the yacht will spend the winter, how to prepare the engine and generator, and how to wash it before it disappears under the tarp for a few months. In the following parts, we will delve deeper into the specifics of wintering on the water, on land, and separately — into the standards of southern Europe, where wintering on the water is the norm rather than the exception.

The first decision: water, land, or hangar?

Before we tackle the technique, we need to answer the question that determines everything else: where will the yacht be from autumn to spring? In practice, there are three options to choose from.

Wintering afloat (at the dock). The yacht remains in the marina, usually moored in a winter berth. It does not need to be lifted or transported, and the mast stays in place, and access is easy — you can drop by at any free moment. The price of this convenience is constant exposure to wind, moisture, and — in cooler regions — the risk of ice formation. This option also requires regular, frequent inspections throughout the winter.

Wintering ashore. The yacht is placed on a cradle, hydraulic trailer, or hoist, and from there to a yard, where it stands on supports under a tarp or in a hangar. This solution provides full control over the underwater part of the hull and eliminates the risk of ice, but comes with the cost of lifting, seasonal yard fees, and the logistics of unstepping and re-stepping the mast.

Hangar or closed hall. The most expensive but safest option — constant temperature, no UV radiation, and the possibility of carrying out maintenance work despite frost outside. It makes sense for vintage yachts, wooden ones, with expensive onboard electronics, or in regions with exceptionally harsh climates.

About how to choose between these options in a specific climate and how to prepare the yacht for each variant step by step, I will write in more detail in the following parts of the series. Here it is worth remembering one rule: the decision about the berth should be made before we start preparing the systems, as it determines, for example, whether the drinking water tank needs to be completely emptied or if it is enough to keep the heating above freezing.

Interesting fact. In regions where it gets really cold in winter, one can encounter unusual attempts to "save" wintering on the water using technical tricks — underwater mixers or aeration systems that aim to maintain the movement of warmer water around the hull and prevent it from being crushed by accumulating ice. Some of these solutions are even patented. However, industry sources agree: none of these methods are fully maintenance-free or reliable, and nothing replaces wintering on land where frost is a real threat. Technical workarounds for a problem that is best avoided altogether are usually a more expensive solution than simply transporting to the yard.

Main engine: step-by-step procedure

Regardless of where the yacht will spend the winter, the engine must be prepared the same way. A neglected engine in winter is the most common item on the spring list of costly repairs — and most of them result from just a few missed steps.

Oil and filter — change while warm

Engine oil after the season contains combustion products and acids that will slowly attack the engine components from the inside throughout the winter. That’s why it is replaced right after the last trip, while warm — heated oil is thinner and flows out more easily, taking contaminants with it. Changing the oil and filter is one of those jobs that cost little but protect the engine all winter.

Fuel: full tank and stabilizer
Here arises one of the few real controversies regarding wintering. One school recommends filling the tank almost to the top (about 95%) — less air above the fuel means less condensation of water inside the tank. The other points out that fuel left standing all winter, especially diesel, is an ideal environment for the growth of bacteria and fuel fungi (the so-called diesel bug), and adding extra fuel in the autumn only increases the risk.
In practice, the safest compromise is: a tank filled with about 95% good quality fuel, with the addition of a certified stabilizer and biocide, and the engine started for several to a dozen minutes after adding the preparation, to ensure it is distributed throughout the fuel system. In spring, before the first outing, it is worth checking the water separator and fuel filter — this is a cheap check that will catch any potential problems before they harm the engine.

Fogging — cylinder preservation
Fogging involves spraying preservative oil into the intake manifold (or directly into the cylinders, depending on the type of engine) and cranking the engine several times with the starter without ignition, so that the oil coats the walls of the cylinders, piston rings, and valve stems with a thin protective layer. This prevents corrosion, which otherwise develops over months of inactivity — particularly severely in humid, marine air.

Cooling system
Here the procedure depends on the type of system:
•Closed circuit (with coolant) — we check the glycol concentration and top it up to the level recommended by the manufacturer (too low concentration will not protect against frost, too high will worsen heat dissipation).
•Open circuit (raw water) — either completely drain the water from the system (checking all drain valves — it's easy to have a 'pocket' of stagnant water that we forget about), or flush the system with antifreeze at the appropriate concentration (typically down to about –35°C for the Polish climate zone).

It's also worth checking the impeller of the seawater pump (the rubber impeller loses elasticity and cracks if it sits 'bent' in one position for many months — some mechanics recommend removing it for the winter/exchanging it), as well as the condition of the V-belts and hoses — this is the cheapest time to replace something that is nearing the end of its lifespan.

Gearbox and propeller shaft
Check and possibly replace the oil in the gearbox, check the trim fluid (the correct fluid is red and clear — a milky or pink color indicates the presence of water in the system and requires service intervention). We lubricate the propeller shaft seal according to the manufacturer's specifications; if the yacht is wintering on the water, we tighten it a bit more than in the season to limit leaking during a long idle period.

Outboard engines
If the yacht is powered by an outboard engine, the procedure is similar but with a few differences specific to this design:
•fogging is done through the carburetor or air intake, according to the manufacturer's instructions (two-stroke engines with DFI injection have a separate procedure — usually, the preservative oil is injected directly into the cylinder),
•we replace the grease in the lower unit and check its color — milky or creamy indicates water in the housing and a damaged seal that needs to be repaired before the season, not after it,
•we check the condition of anodes (replace when wear exceeds about 50%),
•during downtime, we set the engine vertically so that any water remaining in the cooling chamber can drain out by itself.

Generator

The generator on a motor yacht or larger sailing vessel is essentially another internal combustion engine — and requires the same care, although it is often neglected because 'it's just sitting there turned off'. This is a mistake: a generator wintering without preparation has exactly the same problems as the main engine, only usually discovered at a worse moment — when there is no power during downtime.

The procedure overlaps with that described above for the main engine: oil and filter change while warm, stabilizer in the fuel, cooling system check, cylinder fogging. Additionally, it is worth:
•replacing or at least checking the air filter — a clogged or damp filter is a common cause of starting problems in spring,
•charging and securing the generator starting battery just like the main engine battery (see below),
•if the generator is in a separate, poorly ventilated compartment — ensure it is ventilated during winter to limit condensation.

The Starting battery— for both the engine and the generator — is best fully charged and either disconnected for the winter or connected to a trickle charger (maintenance) or a solar panel with a regulator. The batteries themselves and the entire electrical system deserve a separate, in-depth article — here we limit ourselves to what directly concerns the starting of the engine and generator.

Washing the yacht before winter storage

Washing is the last step before 'closing' the yacht for winter — and one of those steps whose omission has the most severe consequences in spring, as dirt and growth that have dried for several months are much harder to remove than fresh.

The underwater part
If the yacht is going ashore, we wash the underwater part of the hull immediately after pulling it out of the water — marine growth and deposits release most easily then, before they have a chance to dry and adhere to the anti-fouling coating. We use a pressure washer for cleaning, but with moderate pressure — too strong a stream from close range can damage the anti-fouling coating or laminate. It’s also a good opportunity to inspect the hull for osmotic blisters, scratches, and damage — this is the best time of year to notice them.

The sides and deck
We wash the hull above the waterline and the deck with dedicated yacht cleaning products, rinsing at the end with clean water under low pressure. Stains and spots (e.g., rusty from fittings) are well removed with baking soda paste — a simple, cheap, and safe method for laminate, before resorting to stronger chemicals.

Deck equipment
Anchor winches, capstans, sail guides, and other movable equipment should be rinsed with fresh water to remove salt, which accelerates corrosion over the winter. The same goes for the anchor chain: the winter lay-up is a good time to inspect it thoroughly and, if necessary, touch it up.

Interesting fact. While washing and performing the winter inspection, it’s worth developing a small but practical habit: refreshing the painted markers on the anchor chain. This detail is rarely mentioned in general guides, yet it facilitates sailing throughout the next season — especially useful when anchoring in unfamiliar bays in southern Europe.

Interior — at this stage only preliminary
Full preparation of the interior (ventilation, drying, protection against mold and rodents) is a topic for a separate part of the series, as it varies depending on whether the yacht is wintering on water or on land. At the washing stage, it’s enough to remove food, damp textiles, and trash from the yacht — before we decide how exactly we will secure the rest of the interior for the coming months. It’s also good to lift the mattresses so that air can flow freely around them.

Photo by David Todd McCarty on Unsplash

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