Yesterday my daughter and her friends went out on her 1989 Hobie 16 which is in terrific shape in winds about 25k. We know it was sporty and they seemed to have the boat under control when all of a sudden the sail seemed to rip out of the mast. No damage to the sail, but the masthead assembly was pulled right off to the starboard side, then pulled right off the mast.
We'll have to buy a new masthead, part 20614001, but you can see where the rivets were ripped out of the carbon fibre. We're puzzled how to repair this:
Should we cut off the 3/4 inch of the top of the comp tip, then replace the masthead assembly? This may have a different effect when we hook the main up by lowering the sail to the tramp.
Should we use West System and glass in that top, then redrill to replace the masthead assembly? Would the glass repair be just as strong?
Does anyone have any advice? I already checked out the Hobie Product Support website and this is not one of their popular repairs.
Wyatt 
When you say carbon fiber... are you refering to the comp tip of your mast? If this is the case than it is not really carbon fiber - just glass with some pigments in the resin. Repair... not having seen a pic I would repair the areas where the rivets have riped out with some resin (epoxy). I would not shorten the mast! You could also drill holes in your new part and the mast in areas that were not effected by the damage and rivet there. Kind of a odd damage - not sure why that happend. I would expect that the lager amount of force goes straight down. Check the general condition of your comptip... they age fast under UV light and heat - the whole thing might be ready for a replacement.
Patrick
As long as the structure is intact up there (no big chunks missing), I would drill new rivet locations and re-install. I too cannot imagine what forces would cause the head assembly to pull to one side. Certainly is odd.