thanks for the comments,
I'm not sure stability is the major issue, as compared to perhaps bad weather and choppy seas which reduce the efficiency of the air cushion underneath. I'm interesting in designing a plane thats intended to go at faster than 300km/h using a small jet turbine for propulsion. As far as i can tell very little research has been done in this area, and the shapes of plane required would be quite different to the slower speed flare wing airfische.

Anyone wanna donate a wind tunnel and 3d printer?

Still, I love the tech, being able to just cruise off land and over water, nothing but the horizon and clear blue sea... it makes me drool.