In any case, now I'm back to the mast proper. For those who don't remember (I barely do myself) I'm doing a modified birdsmouth construction, with a sail track, in Jarrah and Tasmanian Oak. Neither of these are traditional spar making timbers, on account of their density, but I figure I can get good performance by pushing the boundaries of the traditional birdsmouth technique, and thinning out the walls some. Plus, Jarrah and Tasmanian Oak are pretty-much indestructible.
Here's a photo of my prototype piece, that I did a while ago. It's mainly condtructed from 30mm x 12mm staves.
I think I've come up with a workable solution. Davey do chainplates with the eye at 90 degrees, intended for mounting on the stem at the bottom of the bobstay, or else on the gunnel for bobsprit shrouds, shown below:
The whole assembly bolts through the mast with a single 5/16 bolt (actually I'll use 5/16 bronze threaded rod with acorn nuts on either end.
My fingers are a mess after beating on those straps.