The huge wing sail doesn't do that already? Seems to me any little puff comes along, especially 150' up, and those little parking sails will be about useless keeping that thing straight!
Well, no the wing wouldn't. A boat at anchor will naturally yaw back and forth to the wind. If it has any source of lift (above or below the water), then it will tend to sail upwind on its tether. The anchor riding sail(s) is(are) there to impart a big weather helm. They cause the boat to pivot head-to-wind before it sails too far. Two such sails (tacked outboard at the sterns) would turn the boat quite aggressively.
