On my trailer I had to put them as far in as I could. Have a 17-foot Bayliner. Even after tightening the u-bolts extremely tight, to the point where the clamps are actually bending. There was still some play or wobble. I drilled a hole and ran a bolt through the clamp, this right really did the trick to tighten things up.
Rating:
[4 of 5 Stars!]