I posted a couple memes here o p e saw ***** firewood hoarders and Facebook
You're right, now that I look at it I can see that the left hand foil in the video is actually a rudder. Which means one hydrofoil is lifting the entire boat...... That's some crazy strong foil !I don't believe the hydrofoil is doing any of the steering. That be a rudder on the rear of the catamaran. Not sure what you are calling a strut.
They raise the windward hydrofoil (daggerboard) so as to eliminate drag.
That hydrofoil looks pretty close to the middle of the boat.