Stefan Creaser said:
>I also don't agree that the cow's tails can be considered static, made of
>dynamic rope there is some stretch inherent in there, more than a static/web
>harness.
According to the tests, there is indeed a dynamic component to cow's
tails, at least those made of knotted rope rather than sewn webbing. But it
came mostly from tightening and deformation of the knots, not from stretch. On
page 14 they said:
>The results of these tests are all very close to each other, the standard
>deviation is only 0.25 kN, while the ropes used are very different. It seems,
>therefore, that the tightening of the knots has a lot more influence on the
>shock load than the type of rope.
And again on Page 31:
>In order to compare only the types and diameters of rope, we have produced
>averages of the results for each type of rope.
>The results are very close (average of 6.01 kN and standard deviation of only
>0.15 kN or 2,5 %) although these ropes display very different characteristics
>and have varied diameters.
It made little difference what type or diameter (8 - 11 mm) of rope was
used, although dynamic was of course better than static. But the length is so
short that one wouldn't expect a big effect.
Mark Minton
