> My guess is that as the kayak's velocity increases so does the
> resistance to both intitial and secondary stability. Is it possible
> that the force of friction, increasing with velocity, makes it harder
> to tip over? I was thinking of a water skier and a windsurfer, both
> carving turns at speed; both unable to do the same things a slower
> speeds. It would seems that their initial and secondary stability
> increase in proportion to velocity. But, this is just a guess.

Still a guess, but maybe a qualifyed guess. Picture a hull moving through the water. Due to the hull shape the hull has to "push aside" an amount of water in order to make it possible to pass through. Then, when the hull leans to one side, more of the hull at that side of the boat, and also at that side of the boat's gravity center, will be submerged and less of the other side of the hull. When the boat lays still in the water, this gives more static "lift" on the same side of the the hull thus preventing, or at least resisting the force that in the first place causes the hull to lean to that side.

Then, when moving forward (or backwards) in the water, the hull, in its leaning status, has to push aside more water on one side than the other to pass through, and this creates more force (in addition to the static force) towards the leaning force. The faster you move through the water, the larger this force will be. (After consulting my dictionary, I think the key word here is "law of inertia") The same force makes a speedboat lift almost out of the water at high speed but move through the water at low speed.

Did this make sense? If not I'll blame it to my lack of technical english and leave it to others to explain.

Totto