Tiny sailboats rocked from side to side Sunday morning along the Petaluma River, at the mercy of the momentary wind gusts. “Any wind is good,” George Pedrick, 65, who lives in Point Richmond, said.

Almost two dozen yachts — white sails unfurled and flapping in the breeze — race back and forth on a sparkling, blue sky day at Manly Harbour in Brisbane. Passers-by, especially children, stop in awe ...