Mid point of a dry foiling gybe - Te Kahu sailing with four crew - up - Emirates Team New Zealand - Waitemata Harbour - February 19, 2020 © Richard Gladwell / Sail-World.com
While Te Kahu was on both foil arms, she stayed well clear of the water. The critical point of the tack or gybe seems to be the exit when the new windward foil is raised - losing the lift from the wing, but still contributing to drag. The 12 metre long test boat would either stay completely clear of the water or make the briefest of touches, until the full load went onto the new leeward foil and she is up and away.
For the record, on a day that was midway through the Prada Cup Finals 12 months hence, the breeze was blowing down the Rangitoto Channel, from a Northerly direction bowing 10-12kts. It is likely that Course B would have been used for the Prada Cup in these conditions.