[Paddlewise] A Secondary Definition!

Nick wrote:
>>>>>I don't see how the analogy of a ball flying through the air is a
good analogy for stability. A ball is free to fly so the shape of the
ramp may not effect it's travel, but a boat must stick to it's curve.<<<<<

As I said beforehand, there are difficulties with the ball bearing/ramp
(attempted) "analogy". What I was trying to model was how the stability
curve on the backside drops away more with each increase in angle of lean so
it provides no feeling of security (the "stiffness is negative) in that
area. It will not stop a capsize in progress. John kept claiming the
backside was important to the secondary/overall stability (which he thought
were comparable and I didn't) and I was trying to get him to see why it
wasn't. I hope Nick's explanation was more convincing than mine. I think
that only the highest parts of the backside of the curve could be a help and
then only because we can bend at the waist and move our center of gravity to
one side (creating a new stability curve that would have some relation to
the fixed paddler stability curve because some of the backside of the
original fixed paddler curve would, as a result of the weight shift, now be
on the frontside of the new curve). The point I was trying to get across was
that it makes little difference to the paddler what the shape of the
backside of the curve looks like. If you go there with any momentum you are
not going to be righted again unless you brace somehow.
If you look at the shapes of the three curves in the XL review it should be
obvious that it would be in my best interest to argue the exact opposite of
the way I am now. The final capsize point on the XL was at a greater angle
of lean than nearly all the other kayaks tested. Years ago I thought that
the capsize point was important and that the backside had something to do
with secondary stability but newer evidence has changed my opinion.
I think Nick's explanation (if it can be made more understandable to the
non-technical among us) is a good one that fits with what a kayaker senses.
Maybe we can call it "Kayaker's secondary stability".
Matt Broze
http://www.marinerkayaks.com



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