Matt's post basically sums it up, except the "professional" umps (still usually volunteers, but very highly ISAF certified, and often paid for travel) will include a rule number reference with every phrase they speak.

It's hard to be in the guy's head, but every time I rewatch that clip, I think the black boat started to leebow (completely a monohull move, BTW), but went too early, realized he was about to get rolled by yellow as a result, and tried a Hail Mary attack on yellow, which failed miserably. Again, this probably would have worked in less wind, because yellow would have had a bit more time to respond.

Whenever you watch good match racing in moderate breeze, it gives you a whole new appreciation for how fast even slow boat designs can maneuver if pressed. Our fleet racing, go fast and nail the corners strategy in cat racing does us no service when trying to critique match racing on monohulls.

Mike