What Is a Winch?
The drum that reduces rope loads through gearing to human strength — the cockpit’s muscle system and the one fitting that deserves to be opened once a year.
A winch is the drum that makes sheet and halyard loads manageable by hand through gear reduction. A self-tailing winch holds the rope tail in its upper jaws; that is the clever bit that makes single-handed trimming possible.
In a blow, a genoa sheet can be carrying several hundred kilos of load; what holds that load safely are the winch’s gears, pawls and springs. A dry, tired pawl can slip, and the handle can kick back hard enough to catch you on the wrist. Winch maintenance is not a comfort job, it is a safety item.
Annual maintenance
Click test: if you do not hear a clear 'click' as the winch turns, the pawl springs are tired and the service is overdue.
Open and clean: strip the drum, clean out old grease with paraffin, use a light grease on the gears, and only a light oil on the pawls (do not grease the pawls, as it makes them stick).
Take photos first: record the parts layout, and from the second winch onwards the job drops to half an hour.
If the self-tailing jaws wear, they stop holding the tail and the line can run under load. Salted-up grease makes the drum hard to turn; the problem is not muscle, it is chemistry.