Re: [Paddlewise] Secondary stability... another way to think about it

Kevin wrote:


(SNIP)

>
> Now here's my question... the location of the CB with varying degrees of
> tilt should be just as easy to calculate as the bouyant resistive force,
if
> not even easier. Why doesn't someone modify a program to measure this? I
> think it would be a lot easier to quantitatively understand the secondary
> stability of kayaks by this metric.
>

No need to modify the programs. Most already handle this. In Nautilus one
manually alters the transverse and vertical centers of gravity to reflect
the changes. The problem with publishing this kind of information comes from
the differences between paddlers. The curve produced by a good athletic
paddler would not match one produced by me. In any case, the stability curve
shapes remain fairly constant (not always so it helps to actually calculate
them for better accuracy) and one can just add the righting forces together
without resorting to a program and stiull get a good idea of stabilty
characteristics.

 This method reveals the total righting force of the system as well as the
force at any given degree of heel. You can add these righting moments as the
heel occurs or even add them in a delayed fashion to account for slower
reactions. My program can do this and I suspect Nick's MacSurf can do it as
well.

Having done this and compared my perceptions to the curves it appears valid.
Admittedly I have not tried it with a large sample but I suspect that the
perception of righting force will remain reasonably consistent.

Cheers,

John Winters
Waveform Plastics Technologies Ltd.
15 Ena Ave.
South River, Ontario
P0A 1X0




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