Re: C&C Halyard Sheaves
I would doubt anyone would be able to give you the exact dimensions for the sheaves.
I can tell you that they are more than likely dual grooved sheaves. One large groove for the rope and a smaller groove for the wire. They will be held in place by a retaining plate that covers the hole on the side of the mast that the shaft sits in. Remove the plate, slide out the shaft and the sheaves will hopefully fall out.
I just replaced my wire to rope halyards this summer. Three wire to rope halyards were over a $1000. My sheaves were OK, they just needed some lube. The sails drop to the deck under there own weight now.
There are some pretty cool rope products out there and I too would suggest all rope halyards and rope sheaves.
Rope is less expensive to replace and no meat hooks.
If you take your old sheaves into a machine shop they will be able to make you some new rope only sheaves for fairly cheap and it should only take an hour or so on a lathe.
We have three rules;
No bleeding on the sails.
No slobbering on the charts.