: I don't think that the bicycle/motorcycle comparision is the right thing;
: they gain stability by the gyroscpoe effect of the wheels.

: I wonder if there really is a change in static stabilty or if it only feels
: like more stability. The feeling of stability is partially due to roll
: damping which effects how fast the rolling occurs and how quickly it will
: die out. Damping is certainly affected by forward motion.

: It is also possible that there are asymmetrical pressure forces that might
: act to provide some amount of stability when the boat is moving versus at
: rest.

Well. That makes complete sense. I wasn't trying to make a one to one comparison, but i definitely wasn't thinking about that gyroscope effect. Good call-

I definitely think the "feeling" of stability plays a great role. Not that it is a trick of the forward motion, but this got me thinking about the forward stroke. I moonlight as a whitewater river guide on weekends, and one thing every guide learns is that passengers rarely fall out of a raft if they are paddling. Their forward stroke (however horrible it may be) acts as a bit of a brace stroke for their personal instability. Consider the righting moment of doing a sweep stroke (sweep brace, or sweep roll even). I am sure this plays a decent bit into the feeling of stability.

Thinking about it further, the pressure on the hull has got to be the true answer of any real gains in stability. This will of course be very different depending on the hull design. I got to thinking about planning hull shapes and the lifting forces at speed. Those kinds of pressures to a smaller degree on a kayak have to aid stability~