"No matter what method of power is incorporated into a sailing aerofoil concept, a designer will still have to transition the craft from water-contact to freedom from water contact - and this transition can not be achieved STABILY without the application of ground-effect dynamics."

Nonsense!

Try the kite/car keys/parachute trick on a big open field, but this time don't run towards the kite after launching or open the parachute. Just let it trail along the ground after you release it. Any guesses what is going to happen?

Jon.