I'm quite intrigued by the flextail, in part because there's a little bit of a forehead slap here of "how did I not even think of that!"
As is typical with proprietary engineering, the published information doesn't really say a lot about WHY it works. So I am left to MSU (make shit up).
I think I understand one part fairly well, so I'll start there: While in the actively turning phase, the force acting on your ski points roughly inward toward the centerline. Thus the tail flexes inward, which causes it to more resemble the very arc you are trying to make. It seems borderline obvious that such a shape will turn "better" in some way, whether it's holding better or a tighter radius or maybe both. Fwiw, this is a lot like what a fish looks like making a fast turn. (I can see why Fishtail wasn't the name of choice, however...)
Next, let me move back to the preturn phase. At this point, especially on a short line, the force acting on the ski is pretty close to straight down the ski. That means that the tail isn't flexing much. So during this phase this feature seem to be "off," which is totally fine.
Finally, there's what it does when making your way across the wakes. Here I find myself a bit confused. I DO get the fact that this ski can be longer than "normal," because of the turn-radius improvement. So that is a help in holding a good angle. Maybe that's all we're getting during this phase (and that's still great). But as far as the flextail itself goes, it will be flexing away from the boat. Is that what we want? Or is it more like that doesn't matter much because we're using the whole ski against the water and the fin is not terribly important? I think the latter might be true because when we think fin adjustments we almost never talk about what is happening behind the boat: the fin seems much less important at that stage.
One thing that seems plausible is that the flexed fin is effectively asking the ski to add angle. I.e. if you are going from even to odd, it is trying to turn to its right. I can't decide if that would be a good thing or a bad thing?
Anybody actually know anything they can share -- or care to join me in wild uninformed speculation!?
Nathaniel Bogan -- GUT Padawan