Out come all the kite-surfing/fluid dynamics geeks...
everyone's adding their bit to complete the picture, cool

"surf shaped edge as opposed to your standard twin tip square edge and why this is better for surfing?"...
This is also where rocker also comes into play as well as flex lengthways, diagonally and across the width. Fibre/epoxy glass is now manufactured in interesting designs with different gram threads being used in the warp and weave, were not talking 4 oz glass, 18-22 oz sometimes with diagonal threads.

Some kite boards also have carbon fibre put withways just on the tips to help sideways flex and upwind ability without compromising on flex throughout the board.
its all about the subtle curves.......sounds like another topic?

Corey, I disagree. Have you ever objectively tested various boards against each other in the same conditions? You can't say that different boards don't have different riding characteristics, unless of course you're a rank beginner and have no clue what's going on under your feet .

So regardless of the science behind it, just imagine having some sort of skill level and being able to choose from a range of boards. You find that some boards feel really good to ride, and some feel not so good. So you're going to want to buy the one that feels the best.

Now imagine that the manufacturers and retailers understand this, and try to tailor their products accordingly and make appropriate sales based on individual customers. Then imagine that there actually is a science behind it, and the wider understanding of that science is a good thing, because it helps the general public choose a board that's right for them.

Now, back to the actual topic, does anyone have any opinions on channels? As far as I can understand they would work like mini-concaves, but being at the back of the water footprint rather than the front, would that detract from their upwind ability. My personal opinion is that they do, but they make up for it by really holding onto the water and giving a lot of leverage and control. Am I onto anything? What are peoples 'scientific' experiences with channels?

Anyway, I also did fluid dynamics some years ago, maybe 8, but can't remember anything useful from it. Except maybe that the rather incompressible nature of it as oppose to air may make a slight difference to the golf ball effect, but if I remember correctly it was negligible anyway. All I know is that I've got two main boards, I ride one on flatwater, one in surf/chop, and I prefer the flatter bottom one in the surf/chop and concave on flat. Backwards to all the theory, yes, but they are different lengths, widths, rail types, rockers, end shapes, fin sizes, weights, flexs and edge roundness. Plus one has channels and one doesn't (the one that also has the concave, and I prefer it in flatwater). Who can properly know these things hey? But it doesn't hurt to try and understand.