Looking at the overall times for the Tybee 500, I found it interesting to look at the spread between first and last on cummulative time.

I20: 8 hours, 14 minutes
F18HT: 8 hours, 48 minutes
N6.0na: 1 hour, 24 minutes

Seems that the N6.0 sailors were a pretty even match. (The difference between first and second place in the class was 1 minute and 48 seconds.)