Well, sea trials of my newly pre-bent Tornado rig with updated sails were going great...15kts, good power and sail control. Hardened up for another windward leg, loaded up downhaul to max grunt (8:1) and honked in the mainsheet...BANG! The hook at the top of the mast fails and the main drops. Limp home on jib alone.
The hook was not made for the modern prebend loads...metal is about 2.1 mm thick, other boats I compared it to in the yard were nearly double that at 3.8 mm. One 1/4" monel rivet pulled out as the hook bent.
I've sourced a Hobie 18/20 hook which mounts on the opposite side of the mast (starboard) so no worry of fatigued aluminum. Hobie hook is thicker/larger with 6 3/16" rivets. This is made not to pull out of the plastic comptip, so it otta hold real well in alu. Will drill it out to 1/4" and slap in new monel's. Might need to flatten the curve of the hook a bit prior to installing.
Mike.