Help! The plastic sheave in the base of my Z-Spar mast is jammed/broken. This is the sheave on the starboard side of the mast base casting that turns the main halyard through 180 degrees. If you have to pull up on the main halyard to raise the mainsail, you have the same setup I have.I can't raise my main halyard any more without a great deal of swearing and cursing (very disconcerting for the children), and reefing is now a royal pain. Any ideas as to where I can find a replacement? If I can't find one, I will have to cut a slot in the mast so the halyard can exit (and then I will be pulling down to raise the halyard, like normal people). Any help will be appreciated.PeterS/V Raven