Internal halyards? Feed a weighted messenger line (tire balancing weight, fishing
weight, whatever will fit thru the masthead) down the mast from the masthead, until it passes the the exit for the main halyard. Marking the messenger line before lowering it inside the mast wouldn't be a bad idea. Then fish
the messenger line out the exit using a wire snag, and finally use the messenger line to pull the halyard through. This is one of many reasons why it makes sense to keep a roll of thin dacron or nylon line on hand.