Wing sails, as they are called, have been around for years, and one was even used to great advantage in the 1988 America’s Cup. But at 223 feet, this one is much bigger than others (and bigger, in fact, than any airplane wing) and more controllable, with nine adjustable flaps.

Like an airplane wing, it provides lift, although largely in a horizontal direction. And like an airplane wing, the slots between the main elements and the flaps add to the lifting power.

But the wing also solves a basic problem of sailing: how to take full advantage of the wind without overturning. The flaps can be adjusted to maximize lift on the wing’s lower end, generating a lot of power, and to reduce it up top, generating less heeling, or tipping, force.

“You can shift the center of the force up and down the wing very quickly,” said Russell Coutts, chief executive of BMW Oracle. “So when you’ve got too much power, then you can unload the top of the wing.”

The wing designers use the same principles, and much the same software, as airplane designers, said Mike Drummond, the team’s design director. (One member of the team also does work for Boeing, though not on wings.)

“You have to understand the aerodynamic principles well and how to apply them,” Mr. Drummond said. “If you have the skills to design an airplane, you have the skills to design a yacht. Now we could have a good crack at a windmill.”

Load-shifting can be done with more traditional sails, too, by changing their shape, which is accomplished in part by having a flexible mast. But even with technology  one system uses image-recognition equipment to “read” lines on the sails to see if they match prescribed curvatures  shape-changing is difficult. It is easier with a solid wing.