Cracked the tang/toggle on the forestay; 50 foot Tayana FD-12 Cutter rigged sloop

[Byterbit]

Here's a note from a friend, rather far from home, with some issues:

50 foot Tayana FD-12 Cutter rigged sloop with a cracked the tang/toggle on the forestay, and the cutter stay beating in fairly mild conditions with a conservative sail plan. This is a masthead rigged cutter with upper and lower spreader bars. Backstay splits about 10ft off of the deck to two turnbuckles at the deck. Basically with the inner stay (removable) tensioned it imposes a bend on the mast going aft from the second spreader (where it connects) to the top of the mast (which is bent aft). This cutter does not have running backstays. It has the usual lower shrouds to the first spreader, then at the second spreader you have the innerstay fwd and two more that run aft, but not far aft, they share the same chainplate as the lower aft shrouds. This seems to be their answer to running backstays however even after giving them plenty of tension them the inner stay seems to bend that second spreader foward. Disconect the innerstay and the rig goes straight (er). SO my theory is that when sailing offshore with the cutter, as that sail loads and unloads with each wave, its 'pumps' the mast fore and aft, I think this and the rest of it getting loose (from a wet deck and not being sailed offshore for 10 years) caused the failures we had. I'm thinking the solution MIGHT be to tension the forestay to bring the masthead back forward but I'm not even sure I can get to a toggle (or maybe it has been backing off causing problems) since it is under the furler. further tightening on the back stay seems to impose the bend again starting at the second spreader going up to the masthead. If I try and take off the furler to investigate I may end up spending plenty at this expensive marina, as it may take some time plus it is a job I'm never comfortable with even though I've done it a few times SO the question is, am I correct to not want this mast to move very much at all under sail? Is flying the cutter going impose this bend and then cause a stress-loading on the forestay?