Tbh my first thoughts were how lame it would be to be tethered to the lake like that. Bit like the dodgems, great fun but you can only stay in the dodgem arena.

Actually those were my first, second and last thoughts. If in the scale of things jetskiers going up and down a beach in nice weather "showing off" is a 8/10 in terms of cockness, seeing someone with one of these would be an instant 11, initial reaction might be "oh cool" followed immediately by "I bet the person using it is an absolute wanker". And sure enough at some point he (or she) will get too close to some people and either injure them or get them completely soaked.

Quote from: Dave

is the big hose bit properly anchored to the bottom of the lake - or is it just weighted down so it stays in the water?

Would be awesome if it was the case or if someone was able to develop it further.

edit - ah got puzzled by zpyders post

looking at the video again it is dragging a small pod/boat behind it

Its not tethered to a boat, theres a jetski motor that passes water up the main tube and blasts it out the side ones. Motor floats on the water, bloke flies.