The cleat mounting on the beam allows for some additional purchase when pulling the traveler back to center. My I-20 had it on the beam, the F-18 has it on the traveler. I don't notice too much of a difference.
My 20 has the cleat on the traveler. Don't care for it that way at all. When its really windy the traveler moves inboard as you sheet in and it's harder to travel in as well. Having the 2:1 purchase on the traveler with the cleat mounted to center of rear beam is better IMHO.
-- Tim Grover
1996 Hobie Miracle 20
Two Hobie 14's
1983 G-Cat Restored
Memphis TN / North Mississippi --