Your mainsail should have a three foot piece of rope attached along the lower part of the luff, which is external to the sail's luffrope. The track slides on this part of the sail are on the external rope, not the luffrope. When you lower the sail, the external rope hangs lose allowing the material containing the reef tack to hang down as far as the reef hook, permitting the hook to be properly attached. The sail should have been cut with a external rope tail like such.
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