I heard that they plan the racing wind speed envelope to go from 7 to 30 knots. No more whining about 18 being "too dangerous to go out".
It was my understanding that the wind limit (in New Zealand anyway), was due to the big swells that develop when the wind picks up. The fragile hulls could break in half (I recall that it actually happened, but don't remember where). The wind limit gave Allingi the edge because they had a better light air boat. When they came to SF, they raced the same boats in 20 knots because the swells were not an issue. The bay chop is typically 1 to 2 feet. With the higher winds the SF outcome was different, which Larry "the ego" Ellison had obviously counted on. Of course, we are talking about an entirely different vessel in this case.