Thanks, Dave. I should have considered that. Just because the organizers wanted people to limit their speed doesn't mean they would all do it. I was trying to visualize parallel wakes making such trouble, but I thought that roughly half of them would reinforce each other and half would cancel out.

Hmm. If a circular wake intersects a long wake, that would make high peaks of water, wouldn't it? Then add a wind gust of 15 mph. What do you boaters think?
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Yes, Joe. The FIB effect.