Servicing a Gori folding propeller and coating an aluminium Sail Drive leg on a J/92s: why they need different care than a fixed prop.
A folding propeller and an aluminium Sail Drive leg fail differently from a fixed prop on a bronze shaft: they need servicing and the right coatings, or they foul, corrode and stop opening cleanly. On Jamais, a 2008 J/92s on Lake Geneva, the winter haul-out included a full service of the Gori propeller and recoating the Volvo leg.
The propeller was dismantled, not merely brushed. A folding prop has an opening mechanism that collects deposits and silt: leave it unopened and one day the prop won’t fold or open crisply — and a prop that opens halfway is worse than a fixed one. After cleaning, the blades were polished (a smooth surface holds less growth and cuts drag), and new anodes were fitted: the anode is the sacrificial galvanic protection, and a spent anode means the leg itself starts to corrode.
The leg was sanded, then given three coats of Osculati zinc primer — adhesion and corrosion protection on aluminium — and finally the antifouling:
The reason for the choice is specific: these are paints formulated for legs and propellers, so they are aluminium-safe and copper-free. A copper antifouling on an aluminium leg would drive galvanic corrosion. And the prop takes a thin, transparent film on purpose: a blade must stay balanced and fold cleanly, so it can’t carry a thick coat of paint.
A propeller that opens and folds crisply, a leg protected from corrosion and fouling with the products that suit aluminium. It is the kind of work you don’t see — until you skip it.
Why not use ordinary antifouling on a Sail Drive? Because copper antifoulings on an aluminium leg drive galvanic corrosion. You need products made for legs and propellers, without copper.
Why service a folding prop every year? Because the opening mechanism collects deposits and silt: unserviced, it can fail to open or fold. New anodes protect the leg.
Why transparent antifouling on the propeller? Because it stays thin and balanced: the prop folds cleanly and loses no efficiency under a thick coat.
This job is part of Jamais’s logbook. See also servicing the Volvo D1-13 engine.
Protecting the engine-bay woodwork of a J/92s on Lake Geneva with Veneziani Wood Line one-part varnish: why seal it, and why a matt base and two gloss coats.
Servicing a Volvo Penta D1-13 on a J/92s: genuine dated parts, the 12-month calendar rule, two oil changes, and a pre-filter upgrade.
Rebuilding a J/92s cockpit: Spinlock XTS clutches and a Dyneema cascade vang for more power and a cleaner, more ergonomic deck layout.
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