A sailboat moves with almost no sound. No engine noise, no splashing wake—just the creak of rigging, the slap of water ...

The SP80, a 40-foot carbon-fiber experimental boat, is using giant kite sail to propel it across the water at over 80 knots ...

but envision a large windsurfing board with towering sails; there is no heavy keel to help keep it upright like a traditional sailboat. Wind blowing across the sails is the energy that essentially ...