Hi, i'm italian, how in called in technical language....?

Question

this

http://www.youtube.com/watch?v=6rvf_SPfx1Y

not the maneuver but the effect of the boat that "lie down " on one board.. the same that could happen sailing upwind

Answer 1

That's called broaching.

A sailboat broaches when its heading suddenly changes towards the wind due to wind/sail interactions for which hull hydrodynamic reactions cannot compensate. This happens when the aerodynamic force on the rig greatly exceeds the hydrodynamic force on the hull, usually due to a sudden increase in wind strength. In small boats and dinghies, broaching often leads to capsize or a Death Roll.