Cheers TFC, should have emailed you knowing how much sailing you did with the kite early on.
The other thing to check is the bolt on the underside of the front beam holding the dolphin striker just before going into the hull. If someone put a saddle real close to it for a righting line then you tend to get cracks lining up all 3 holes after 3 or 4 seasons. This saddle really should be put perpendicular to the hull and at least 2 inches away. Only thing to do is replace the beam in that case.
Heard that from a few 4.9 sailors now. This may be the reason why some front beams have been replaced. Other reasons I can think off are as follows.
Modifications to beam fitting layouts particularly barber hauler.
Mast falling whilst rasing or lowering at a bad angle with mast step pin in.
Older boats need a re-fresh
