Re: Wire halyard through random block.
A white sheave sounds like nylon. A wire halyard will likely cut through it like.... butter. The ONLY reason to have a wire-to-rope halyard on any boat in 2013 would be for a museum display of a boat from the '70's or before. Modern synthetic fiber line is actually stronger than the same diameter wire, and stretches (the reason wire was originally used) less than wire. Splicing wire-to-rope costs so much that even an expensive extra-low stretch synthetic full-hoist halyardoften ends up being cheaper than a wire/rope halyard. The full-hoist line can also be reversed, doubling the life of the halyard. We replaced our wire/rope halyards more than ten years ago, and haven't needed to reverse them yet. Even if your wire to rope halyard was given to you as a present, I would take it off and go with a low-stretch synthetic line. Besides wearing through the spinnaker crane block, the wire is going to develop soldiers that will cut the hands and fingers of foredeck crew, as well as possibly snagging sails. It's simply not worth it.