Be sure and use cradles with your F16.
I tried using the CatTrax in the standard Hobie 16 configuration with my Blade. Bad idea. Without the cradles the boat can shift port and starboard on the axle and the hulls got scratched quickly and deeply from the wet, sandy wheels rubbing on the inside of the hulls. <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />
I installed the cradles made by VectorWorks and have had no problems since.
John D.