We are having a hard time raising the mainsail the last couple of feet on our 2002 Hunter 270. The mainsail in new and heavy (over 7 ounces) but not full battened. One of the problem fixes we are considering is replacing the sheave at the mast top for the mainsail halyard, possibly with a ball bearing sheave, and hopefully with a larger sheave that would have less friction (if space in the masthead casting permits). We would appreciate advice from anyone who has worked on the mainsail mast-top sheave.