: I think the practice of giving a 10% decrese in strength while getting
: nothing in return is stupid. You are free to say it is not.

If the above really holds true, then of course one must agree with you. But where do those formulae come from? I hope not from some engineering manual treating the structural mathematics of eg. steel rods, pipes, etc. Sorry about the scepticism, and thanks for including that link, the discussion there makes interesting reading.

But the testing method, those sand buckets, thats baloney: using point loads to test paddle shafts is nonsense, since point loads are practically non-existing during normal paddling, unless one calls stepping on one's paddle normal.