When nautical vessel becomes hydro-plane?

I was browsing some threads and notices this one: http://www.boatdesign.net/forums/multihulls/hydroptere-61-knots-70-15mph-peak-37448.html and noticed that the "Hydroptere" appears to have aero-foils holding amas. Considering closeness to the water, the effectiveness of the foil is much increased, thus providing additional lift. This triggered the next iteration and I have a question.

And the first question is: "When a nautical vessel becomes an ekranoplane driven by wind?" (REF: https://www.google.com/search?q=ecr...afa3276b4a0233&bpcl=37643589&biw=1671&bih=896 )

My second question is: "Is an airplane or ekranoplane with a keel touching the water to provide lateral stability and which is driven by wind is it considered to be a nautical vessel?

My third question is: "Is it a flying boat or sailplane?"

I just want to know if a something planning above the water, balanced and has a piece of the body which is touching the water and going "120" mph is considered to be a nautical ship? I know it is not easy, but very achievable to have a wind glider with a fin skimming the water to have speed records...
Could someone please explain to me the difference? Not that I degrade the achievement of this endeavor, but my last question is: "Where is the borderline?"

http://www.youtube.com/watch?v=V8Nu94khHoo and http://www.youtube.com/watch?feature=endscreen&v=bbecl88NsEQ&NR=1

 

In the US, the FAA and the USGC have reached an agreement that that non altitude independent WIGs/ekranoplanes operating over the water are vessels and are required to meet all requirements of vessels.

So for the questions in the US.

1) If it requires close proximity or contact with the water, it is a marine vessel.
2) It is a vessel.
3) It is neither, it is a dynamicly lifted vessel.

FWIW, what you are thinking about is not new. In the mid-1970's a speed sailing vessel using a pod with a depressor powered by a Rogallo wing sail was postulated. I really don't think anybody is serious about going fast right now, much like the LSR. All the technology is in place, you just need the will and the money.