Some non-sailors trying to understand what’s happening in the America’s Cup have emailed to say that they are puzzled by the ability of trimarans and catamarans to sail faster then the wind. The answer is explained by some relatively simple physics.
First, no sailboat can exceed the wind speed when heading straight downwind. We’ll see why in a minute.
But to understand how they sometimes can go faster than the wind speed, imagine sitting still on a bicycle with the wind blowing directly from one side at 10 miles per hour. That’s what sailors call… Details