I owned a TheMightyHobie18 with lots of play (Hobie wobble). Tramp tightness was critical. There is a Hobie tightening tool that works very well for the tramp.

I found the beam bolts often worked themselves lose. I even had a bolt completely fall out at 1 time.

We removed the rear beam for some reason, only to find cracks in several places where the beam and bolts met. A quick trip to an alum welder handled that.

I would check that if all other "fixes" dont handle the "wobblem". - I think i just made up a technical word <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />