Food For Thought

[Bill Roberts]

Foiling Boats, talking about foiling sailboats: A sailboat is a vessel for travel across water that is powered by the wind acting on sails. The vessel travels across water either in the displacement mode or a planing mode.
What is a device correctly called that flies above the water using sails or wings for propulsion and is supported by foils, lifting devices, operating in the water. This vehicle takes off from and lands on the water but at " design point" it flies above the water being supported by foils, wings, operating in the water and is propelled by the wind.
Is this device more correctly considered a sailboat or is it a form of a glider that operates in two different medium and uses airfoils to operate or fly in both medium? The hulls of this vessel do not touch the water at design point operation, when foiling.
Well, how about this: An airplane has wheels and it takes off from land and lands on land. Its design point is to fly through the air on air foils.
It is not called a car or truck just because it has wheels and uses them for take off and landing. It is called an airplane because that is its design point.