I agree with Scott
The issue on the jib fairlead position is essentially the leach. One could argue til the cows come home that the angle of attack is changed, but that's only because jib fairlead tracks aren't straight when it comes to the trigonometry of a line between the forestay and the jib fairlead when the fairlead gets moved. If the jib tracks were in line (same angle of track to forestay) with the original position, this would be true, but no boat I know of is wide enough for this to happen. Think of this from a bird's eye view. But that's NOT the point of this discussion.
If you move the jib fairlead forward, the leach tightens, as Scott has correctly noted. I don't particularly call that stalling the sail, but it will actually do that and will also loosen the foot
if you do it too much. So, he's right, that could be called stalling.
I don't have that "stalling" "option" because the way my two jibs are cut and the length and position of our jib tracks, I simply cannot move the fairlead any further forward because they stop there(!); we only have a 110 and a 95. Those with larger overlapping headsails over the size of 110s can easily move the car too far forward to exhibit this example. The leach gets tight, but the foot opens and flaps around. Try it on your boat.
If you move the fairlead aft, the leach will open starting at the top and the foot will tighten. Too far aft and the leach will flutter.
For any given wind strength, the "proper" setting of the jib is to balance the foot and the leach tension, primarily the leech tension.
And, of course, for any individual setting (jib fairlead position) this correct position will change with varying wind strengths.
When the wind gets too strong for your sail set, you have two choices (
ignoring the mainsail for the moment):
1. You can furl it if you have a roller furler (not a roller reefer). Accordingly, you'd need to move the fairlead to compensate for the change in the clew position to balance the leach and the foot.
2. If you only have a hank-on sail, so you can't change the amount of sail that's there, you move the jib fairlead AFT to open up the leach and dump air from the top of the jib to depower it.
For Joe and Tommays: you're right that IN BETWEEN these basic large movements of the jib fairlead positions there are adjustments that CAN be made to the jib. My point earlier and here is that the gross settings do what I describe. The "fine tuning" that's available is a completely different subject.
They've written BOOKS about this.
