Sailors are strong, but the power of the sails is even stronger. Before the invention of the winch, which multiplies the force, sailors used hoists, sometimes pulling on them in large numbers!
Indeed, the pulling power of the arms is about 40 kg for an adult. A little more if he can add the power of his back by wedging his feet for example. In any case not enough to support the power of a genoa on a modern cruiser.
Once again it is the regatta that will provide the solution with the appearance of the first winches for the America's Cup. It was on Reliance in 1903.
A winch is a kind of gearbox. A crank operates sprockets that turn a headstock on which the rope is wound.
The importance of crank length
For physical reasons, the longer the crank, the more strength the crew member has (it offers a larger lever arm). For reasons of homogeneity, the standard length of a crank has been set at 10 inches (25.4 cm, thank you English!). All winch force measurements will then be indicated with this crank size, even if there are shorter ones (manufacturers offer uassi cranks of 8 inches or 20.3 cm).
How do you read the number on the winch?
The sizes of the winches are indicated by numbers: 20, 30, 40, 44, 48... Small numbers for small winches and vice versa for larger ones. This figure means that if you exert a force of 1 kg on the crank, the winch will exert 40 kg on the rope (for a 40 winch) and this for the speed with the greatest force (especially on 2 or 3 speed winches). All these data are theoretical since in reality, friction causes some loss.
But fortunately the sailor is stronger than 1 kg, we have seen that he can exert up to 40 kg of traction. Combined with the winch, this will enable him to tuck in the jib!
