"...achieved a speed of 27.7 mph (44.6 km/h) sailing directly downwind in 10 mph (16 km/h) winds: almost three times the speed of the wind." Very counter-intui

"...achieved a speed of 27.7 mph (44.6 km/h) sailing directly downwind in 10 mph (16 km/h) winds: almost three times the speed of the wind." Very counter-intuitive. At least for those of us not familiar with sailing. And even more counter-intuitive: "In 2012, Blackbird also demonstrated sailing directly upwind with twice the speed of the wind."