: Here's my take on "why": Because water optimally flows under the
: kayak and runs more or less straight from front to back along the buttock

I'm curious about this; how did you come to this conclusion? I'm personally thinking that cleaving the water to sides and bottom would be most efficient way in higher speeds. Trying to force too much water under hull can easily make the "rocker effect" where stern creates suction a bit higher speeds.

: The numbers you're running are not shown significant differences because they
: are NOT flow simulators. They're simple calculators factoring areas/ratios
: and such and can't account for the differences in the bow shapes.

I assume Kudzu used Freeship's Kaper. I prefer Michlet because it really calculates the water flow.

Freeship can show water flowlines when pressing alt and clicking a spot underwater. However I couldn't estimate speed by looking at the lines.

Kudzu, you can send the current models to me and I could run them through Michlet if you want. I assume the flat bottom bow should do fine in flat water - not in waves.