The vortex formed by the end of a wing/foil/sail is a big contributor its drag. We use a number of methods to mitigate it including twist in sails, foil wing tips, elliptical fins, etc.
Here's a fun method of seeing them
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The vortex formed by the end of a wing/foil/sail is a big contributor its drag. We use a number of methods to mitigate it including twist in sails, foil wing tips, elliptical fins, etc.
Here's a fun method of seeing them