Ellen,

 I have already profited from your disaster. I think I was using the same shackle. Now that I am alerted, thru hindsight, I can see that the shackle was too light weight. I had other shackles that were much beefier - but were not wide enough. So - hie me to West Marine and I bought a very beefy shackle and much wider. The load on this new shackle is 8800 #. A wider shackle is the way to go. As you can see from the attached pixs, the pin was bending and had a worn grove. So what happened to you would eventually happen to me. The shackle that I took off - I cut off because it was easier (as you can see in the pix). To hold up the mast to remove the head stay furler, I tied a line six feet or so up the mast and went forward to around (and under) the bow and then back to my winch. I loosened the shrouds quite a bit (and the back stay). I used the winch until the head stay was loose. Since I felt confident the mast wouldn't fall down on my head, I disconnected and put on the large wide shackle. Much relief.

Again, thank you for sharing your grief and pictures. Lesson: always use hardware that looks oversize. By the way, the make of the old shackle is Wichard (French) which is supposed to be excellent quality. In this case, it was much too small. (maybe OK for a halyard).

Tom Brand