Okay,
just contacted Team Nissam, Jörg Gosche.
The conditions were 30-40 knots windspeed achieving "ridiculous" 20.0 knots of boat speed.
He wrote, that due to the width of only 20 yards there were no real options to pick up speed. You simply could not bear off when you needed it, so the options were, sheet out when the gusts hit, or not to sheet out - but then we flipped.

Fritz