Marsh Jones wrote:

That knuckle.

Ahh, the forefoot :-)

I can't explain what you described. When I've seen racing kayaks in
competition, the forefoot is usually buried and the foredeck can be seen rising
and plunging due to the action of the paddler.

The only time I notice the separation point moving aft with speed is when I'm
riding a big roller - I know I'm on the wave for a short bit of surfing if I can
see the separation point move aft to a certain point and the sound is just
right. On a breaker, this doesn't happen as I have to try to avoid purling.

Mike