The mast head has a built-in crane for the main halyards and internal wooden sheaves for the jib halyards, separated by a central divider. I built this assembly as a separate unit, so I could insure that all the exposed areas around the sheaves were well-coated with epoxy. In addition, the bearing surfaces of the sheaves, which are made of mahogany, are glassed over and then coated with an epoxy and graphite compound for a smooth, durable surface. You can see the black graphite epoxy coating in the photo below:
The masthead also has solid blocking around the crane area. To get a wiring conduit through this area I built the blocking with a channel just wide enough for it to pass through in the center. The conduit is flexible plastic irrigation pipe, with an I.D. of 1/2 inch. One of these in each mast half should give me enough space for a VHF coax, 12-volt circuits for a masthead tri-color and anchor light, and a cable for a Sea Me active radar reflector.