The small crack is on the inner middle section of the dagger board well right beside the jib track.
There are 4 access caps on the port hull and 3 on the starboard hull.I think that is where the water came from.
WOW! That’s a lot of ports. It’s easy to believe that one or more leak. I would silicone all of them up and your jib tracks as well.
I've seen a few mystere's that have the jib blocks on the front cross beam, does the jib have to be cut?
Yes you would defiantly have to cut the jib. Mystere’s have overlapping jibs (go past the mast). I have seen people convert to a self tacking jib (the track is on the beam) but never saw someone mount their jib blocks there.
Can you just screw the fittings on the cross bar
I guess… but I would never do such a thing
If you are 100% set on this modification (not sure why someone would do this).. I would look into tracks and sliding blocks like a hobie16 uses on the beam
what are the implications besides more room on the trampoline? What year is your Mystere
Yes, room on the tramp is the only reason / advantage. BUT you lost the ability to move your jib leads in and outboard (a good feature for upwind (inboard) and downwind (outboard). The sliding feature allows you to also make adjutments for up/downwind but not sure how many people use that. I use them more for when I am switching between a 5.5 and a 6.0 jib (you basically set the angle to intersect the middle of the jib)
IMHO a better way to clear the tramp but not have to cut your jib (and loose a good deal of down wind power) would be to remove the 4 way adjusters that go across your tramp and simply attach the jib blocks to the sliders on the tracks. You would suffer a little upwind, but not downwind.
My 5.5 is a 94 I think