I was watching the Virtual Eye overhead view at the time and all I could really tell was that the crossing was very close. I didn't even see the penalty indicator until the boats were halfway down the reach leg. It's a pity that the umpires made what they now consider to be a bad call, and that there's no redress for Artemis.
It was my understanding that mark 6 is a rounding mark, not a gate, but I'll have to look into that.