J/30 Class Association Forums J/30 Forum The Smack Winter Series starts January 4th!

Rick,

If you have the lowers tighter than the uppers, I think that leads to the main inverting and the bubble you see. Most of the tuning guides have tension on the lowers equal or less than the uppers. A good check is to have someone sight up the mast when it is under load. You should see it the mast in column with a slight drop to leeward at the spreaders. The top will fall to leeward just by the design of a fractional rig.

Start adjustments with the mast in column at the dock and get your base rig tune. Take measurements with backstay loose, then look at the difference with backstay tight. Once that is done you can make equal adjustments to the turnbuckles underway. I mark the deck with arrows by each turnbuckle so there is no doubt which direction is tighten or loosen.

You'll find the tune may be different if you have different mains.