The F20 never foils as such, its not designed to do that, the C boards are there to give a minimum lift to slightly reduce wetted surface area of the hull, that minimum lift clearly can be seen when in the video with the rear down to give max angle of attack, the boat raises only a few centimetres and then when the angle of attack becomes too much, the boat settles down in the water. Note how much speed was lost from the very draggy foil at max angle of attack.

There has been some discussion within the A's as to its merits and failures and in what conditions they do work. As much as Macca states the A is not comparable, sorry but the boat speeds are not unsimilar and that is what produces the lift regardless of how much horsepower you throw at getting that speed.

This boats speed is probably as much from modern hull design learnt from the Americas cup as from its C boards, the boards are simply not big enough to foil and the boat too heavy to allow true foiling.

As with all things though there is a down side to foils ( as per the foiling C Cat experiment ), the C boards will magnify and slow the boat through additional drag as soon as they are not in optimum AOA and my guess it will be slower in the lessor sailors hands than one with simple straight boards as they will not have the experiance to know how to balance the boat as well as the pros can.