I don't know but I assume there is two things:

1. Viscosity of water makes is harder to displace water when moving.

2. Paddling is a constant motion where party subconsciously paddler is making small corrective moves on each stroke. Try stop paddling and hold our paddle high - you'll notice it's much more unstable.

Toni.

: I asked this on a boat design forum and got some responses but none really
: explaines what happens. Wonder if any of the designers here can really
: explain this. When a kayak is in motion it gains stability, anyone that's
: paddled a skinny kayak knows this, they are much more stable once moving
: than they are sitting at rest. Trying to figure out why this is, is the
: question. Actually looking at the water around the kayak at speed, wave at
: the bow, hollow under the middle and wave at the stern it should be less
: stable, but it isn't.

: Bill H.