RE: North Carolina Windfest
James and o2benme have it right.
Pick up a smaller weed fin (Tangent Dynamics Reaper 42 would be my choice for you 85 cm wide F-155) and you can sail in the shallower watger at Hatteras just fine.
Also, if you practice turning your board around backwards and sailing out through the shallow water with the fin held up above the bottom, you can enjoy Hatteras on the F-155.
Takes some practice, but it's a great skill to learn as if you ever lose a fin, you can sail back in on the nose of the board in most circumstances.
Just take some time when you first arrive in Hatteras to determine where the really shallow areas are, and avoid them.
Taking off at full speed, in unfamiliar waters, can get you a monumental catapault very quickly.
Hope to see you at the Frisco Woods Windfest!