hmmmm. I like the idea of the captive shackle, but......I don't think it will clear the round part on the block.
For the jib tack, will a 1/4" captive shackle clear the chain plate? Anyone have any experience with this. I see no need for the quick release.
On the class x, my grandparents used to tie a spare batten tie through the hole for the seizing wire and wrap it around the shackle.