If anyone wants to see the cracks I found, go to:
Photographs © Dean Abramson
as the pix have been updated.
I will replace the turnbuckle.
I only want/need to replace the lower turnbuckle. The rod seems fine. I have taken it all apart; it was simple. From top to bottom it's a toggle, turnbuckle with eye, rod, turnbuckle with eye. You loosen it all by turning the rod
which has flat spots for a wrench. I was amazed how easy it all came apart.
I would be happy to replace with a bronze turnbuckle, but am yet to find anyone who makes bronze ones of that type and size. ??
Dean, I understand that you want to keep the costs down. But, please keep in mind that the rod is just as old as that turnbuckle and is made of the same material. Rod is nothing more than single strand wire. When it goes, it doesn't give you any warning. Did you carefully inspect the cold heads? You do realize that the part of the turnbuckle that you have photographed is only one half of the turnbuckle right? The other part, which you didn't photograph is attached to the rod.
Keep in mind also that the bobstay is one of the most heaviliy loaded stays on the boat due to it's shallow angle.
I would strongly advise you to bite the bullet and replace the bobstay entirely. FWIW
Also, If you have a Navtec turnbuckle on the bobstay, I would not be surprized if you have them on the rest of the rig as well. If you do, it's likely that they are of the same vintage. I hope you've inspected everything carefully.