Eric,

Because of the speed of these boats I've heard it argued that the zone can change and become 4 or even 5 boat lengths in this weather condition and at this speed.

For that reason I find that SD/red had to jibe to keep clear of PU/black. SD/red made a sudden move to windward and contacted the skipper of PU. PU was also leeward boat of SD/red. Therefore I would find SD/red solely at fault for not keeping clear of leeward boat.

Just my opinion.