: Hello all,
: I'm part of a team of sixth-form students partnered with an engineering
: company trying to find applications for a new carbon-fibre composite. I'm
: investigating kayak paddle shafts. I already know they can be made from
: aluminium and
: carbon/glass fibre/kevlar composites, not to mention wood.

: I would like to do a mechanical properties comparison between the new
: composite and the existing materials, however I ran up against a problem:
: the paddle manufacturer sites I have visited do not specify *exactly* what
: kind of composite they are using (e.g. 30% glass fibre, 10% Kevlar in
: polyester resin [no, I just made that one up :-)]).

: Does anybody know of the website of a manufacturer of this kind of tubing
: that will have that kind of information there?

You might check the Thomas Register for Skypole, they are a manufacturer of pole vaulting poles and were the the first source for glass paddle shafts. The paddle shaft O.D. is 1.200. I don't know the wall thickness.

: I know composites are synonymous with 'horrendously complicated', and
: different manufacturers will be using different kinds, but even some idea
: would help enormously.

: Also, what kind of Aluminium is commonly used to make shafts? (e.g. something
: like Aluminium 7075 T730)

Before the Skypole shafts, most shafts were Aluminum 6061 T-6, 1.250 O.D. with a wall thickness of .049 and sometimes .042.

Hope this is helpful.......Reg

: And some general questions: Are carbon fibre shafts not recommended for white
: water paddling because they are brittle? How dangerous is it to have a
: shaft break in use?

: When choosing the flex in the paddle shaft you're trading efficiency in
: paddling against comfort (am I right?) So what does it actually feel like
: to use a paddle with a very high or low flex (I've used a kayak before,
: but not much)?

: Any help would be much appreciated

: Stephanie Kocura