Does the F18 have ratings for 1 up or 2?
No.
Could the F18 be a uni without the jib?
There is a modifier that can be applied to those boats that aren't normally thought of as singlehanding- or were never designed to singlehand. The issue with the F16 is that it is meant to be sailed 1 or 2 up.
I am sure plenty of people sail F18s solo occassionally, but I seriously doubt many people race them that way. Besides, I have a hard time righting the blade every once in a while, I can't imagine trying to right a 400lb cat.
