Originally Posted by Ghost
You are correct in that they grow their contact patch out from the centre. The sensation, however, is as I have described. How much so, of course, will depend on individual ski design.
Regarding wider fully rockered skis and carving...
This runs counter to my understanding of fully rockered (reverse camber) designs. And to my experience with them. While I am a pretty middle of the road skier, I have spent many days the past 7 years on a range of fully rockered skis. Including among others Pontoons, Praxis Powderboards, Volkl Kuros, the first gen ELP Goats (no flat spot worth mentioning), EP Pros, Hell Bents, and CCR Praxis GPOs. None of these has any camber. The designs vary. - some are meant to be carve capable. Some not so much. I have at least a couple dozen days on each - with the exception of the CCR GPO which has seem maybe a half dozen days so far. I have demoed a range of others. And I have many days (easily north of a hundred, maybe two) on hybrid camber/rocker designs as well.
With none of the fully rockered skis did I ever notice the phenomenon you are speaking of in a carved turn (or with the hybrids for that matter). The ends of a couple of these (notably the goats and Hellbents) could catch in just the wrong depth and flavor of layered snow - but that's a different discussion than carving. The common theme here is that on hard snow or softer vanilla snow, the skis among these that are designed with carving in mind start with a short contact area. As you tip them, more edge comes in contact with the firm or slightly soft snow. Skied right, they can carve with a pretty decent running length at the apex of the turn.
Of course they do not handle the same as a conventional cambered and sidecut ski. They usually want to be skied a bit more centered overall. They are "looser" when you want to release a turn or skid one - because the tips and tails come away from the snow as they start to roll toward flat (and the running length retracts). So interestingly, they are less likely to catch in crud or refrozen snow.
They have a smaller "sweet spot". And within that sweet spot, they want the turn subtly engaged at the front of the foot and pressured slightly to the back a bit as the turn finishes - because you "manually" control where on the edge the ski is pressured vs camber distributing forces to the tip and tail edges. Not surprisingly, they do not grip at the tips as you enter the turn. Nor do they pop off the tail (or not so much anyway) - because they start and finish in a turning shape - and with the tips away from the snow anyway. Even if you can use their sidecut to deform them somewhat tighter - you never had to apply force to decamber them in the first place - so there is no stored energy to return with a "pop"...
In general, they are a bit twitcher carving on hard snow than a ski that is more conventionally sidecut and cambered - which is hardly a surprise as the ski does little to help distribute force to the ends when it is on edge. It should be clear that while carve-able, their design center is not focused on optimizing carving. (i.e. if you your skiing is focused on carving on ice, a fat rockered ski is probably not your number one choice )
But never have I found them to have a grappling hook kind of catch as I entered a turn. Rather, just the opposite. The entry and exit tend to be rather incremental and "damp". I'd imagine one could design a ski with the right combo of rise and sidecut to make that catch happen (via a chosen rate of width increase faster than the rate of rise) -- but I'm pretty sure the goal and the achieved result is generally the opposite.
Which skis have you noticed this phenomenon with?