Winches.
When you sail with novice sailors or those who have not been on a yacht for a while, it is very common for them to wind the head sail sheets or halyards the wrong way around the winches.
This can cause confusion and delay when tacking or handling sails. Occasionally this can lead to dangerous situations, especially at night or if it is necessary to react quickly
A simple low-tech answer is to mark a big red arrow on the top of each winch in the direction of rotation.
This solution is so simple, that II think that winches should be made with this arrow embossed on the top. Perhaps one day a winch company will do it!
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