Those things don't exactly bob around much...and how many AC boat have you seen with sail winglets?
How many did you see with square tops tin the previous AC event?! They are not exactly quick on the uptake!
I asked the Prada sail designer personally ten years ago why they had no square tops and he said "Oh, too much construction".
Check the top of the new mast of the Big Dog tri. Small winglets I think.
