Let me try to work it out.
*Mast has excessive prebend so headstay sag is excessive. Thats checks out.
*Top of main won't behave because the backstay is too tight, creating excessive prebend. The backstay is a fixed length, and it's tight because the maststep is too far aft, which places the masthead more forward than the backstay wants to allow. The mast never becomes straight. It's like you always have some backstay trim on, even when the purchase is fully eased. Consequently your top batten and the top of the main refuse to trim up. They spill. The top batten won't align.
*When you move the step aft to class position, you'll tighten headstay sag and you'll actually have a straighter mast at the mast head. Your main will look better upwind and your boat should perform better in light air upwind and downwind.
Last edited by 311 Temptation; 01/09/12 10:01 AM.
