After reviewing the play!: The Nacra Infusion and ARC 22 are both barging. The ARC 22 comes up after realizing there is no room above the N20, making contact with the Infusion. (Time to react?) The ARC then bears away and approximately 2 seconds later makes contact with the N20.

I think there is a possibility the Infusion could be at fault being that the ARC tried to come up to avoid contact with N20. In doing so the ARC makes contact with the Infusion, then bears away to avoid further contact.

Also contributing is the fact that it is not a 1 design race, so boats have varying speeds per point of sail. And the start line seems to be set up on a starboard beam reach so the boats cannot slow down by pointing perpendicular to the start line. Therefore boat speeds are pretty high, not allowing much reaction time.