[Paddlewise] Stability

Nick wrote;

.> It is also based on the standard naval
> architecture definition of Initial/primary stability which is the  slope 
> of the stability curve at zero degrees of heel. 5 degrees is  much greater 
> than zero

Fair enough but I wonder what the numbers were. I printed out the graph and 
although it was not super neat and clear it looked like there were 
differences and similar slopes to what I got. If you can send me your data 
and hull shape information maybe I can run them to confirm your findings.

> My "V" bottom sample has plumb sides and a chine below the waterline.  As 
> soon as the chine on one side leaves the water (around 10 deg in  my 
> example), the stability starts to fall off rapidly. A pure "V"  bottom 
> with chines or eventually a sheer above the waterline and the  same 
> displacement, waterplane shape and CG height will have the same  initial 
> stability by this definition, however the slope won't be  maintained for 
> very long, so 5 degrees is enough for a big change.

Not sure I would consider a 5 degree heel as a lot.  In any case the best 
way to deal with this is to use your information to confirm your findings 
since it seems that my shapes (actually similar to yours) may not provide 
the same results even if it looks like they do from your graph.

Cheers

John Winters
. 
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