Sport boats are a different animal, while we may know to go 'bow down and go fast' it's still a bit odd to ease jibcar to 10' even 11 degrees, sheet main out & go 6 (plus) knots. But w/ speed the foils work better. That's the back story. Many of us have been pulling our vangs as hard as we can, but (for some of us) if the vang is two-blocked, it doesn't matter how hard you pull, all you could possibly do is mash sheaves together. Look inside inboard end of your boom. If the 2:1 purchase is w/in a few inches of inboard end of boom you simply don't have enough range. Solution is very simple----just tighten the skinny vang line that exits the top of boom and goes to the 3:1 purchase on the vang. We don't ever want to be close to two blocking in breeze. perhaps you'll have to ease that skinny boom line in light air if your vang doesn't ease enough. Simple to do.
I had noticed this too. How many inches should the gnav shoe be able to travel? Mine looks like it has a 4" range.