ANTHONY KOTOUN was raised on the water, sailing dinghies in the Virgin Islands, before becoming an All-American sailor in college. But none of that prepared him for the shock of his first voyage in a hydrofoil sailboat about nine years ago, when he was in his 30s. With the vessel’s hull lifted several feet above the water’s surface, balanced on what resemble skinny skis, Mr. Kotoun hit speeds he never dreamed he could attain without the help of gasoline and horsepower. The only sound was the taut flutter of the sails above him.

Mr. Kotoun has since won multiple national championships piloting a Moth, the smallest established class of “foilers,” as these preternaturally fast sailboats are known. “Extremely fast and incredibly quiet” is how he describes the sport. “I can tell you this. It’s not just kicking your feet up and sipping wine.”

Indeed, as a new fleet of more accessible foilers sends amateurs tearing across the water at nearly 30 knots (or over 34 mph), in winds half that speed, the pastime is starting to appeal even to the gin-and-tonic set.

For years, sailors have essentially been divided into two camps. In one: the casual boaters who just want to catch enough wind to enjoy a peaceful afternoon on the water. In the other: racers chasing down the newest speed-boosting technologies. Recently, the bleeding edge on the latter front has been the foil—a daggerboard, made of carbon-fiber or aluminum, that lifts the hull out of the water so the boat can go faster with far less power. (The approach works because pushing a hull through the water rather than over it creates drag; worse, resistance increases with speed.)

But those two camps are quickly converging as foil designs get safer and everyday sailors clamor for the high-octane experience they see in the America’s Cup race, where the lightning-fast boats are all foilers.