Mast head sheaves

[rad]

I am in the process of rigging and rewiring my '77 Hunter 30' mast. My question is about the sheaves. They have a channel in the center for a wire halyard. How do I tell if they are a multi use sheave used for rope or wire? If necessary I would go with a Garhauer sheave.

 

[shorty]

Resource

Do not know the answer to your question but here's an interesting resource if you ever need a sheave made