Depending on the wind received by your boat, one of your sails will be faster than the others. In the sail selector, the speed at which a given sail will propel your boat is shown depending on the weather conditions. You can choose the one that is the most adapted to the weather and that will use it to its advantage.
If you possess the "Automatic sail" card, do not hesitate to use it! Your boat will automatically choose the best sail depending on the upcoming conditions for the next 12 hours.