Good Page and New Innovations - Not!

Good Page and New Innovations - Not!

Post by Carl Dougla » Sun, 23 Aug 1998 04:00:00


Quote:
>Hello All,
>       http://www.vt.edu:10021/eng/mech/tidwell/me4016/index.html

>       The above page is a really good site about redesigning the rigger to
>make it more efficient, lighter, and easier to adjust.

With respect, the result is crude, non-aerodynamic & likely to be
troublesome.  Grandly presented, the project lacks substance fails to
achieve its objectives.  Had a fraction of the effort put into
presentation been devoted to greater research and better engineering,
that might have been more useful.

Quote:
>  I also have
>ideas about redesigning the current oar to make it more efficient by
>keeping the blade perpendicular to the boat at all times, but I don't
>yet have the resources to do the extensive research and development

The what?

Quote:
> that
>the ME4016 crew did.

You may have missed the very recent thread on Blade Mechanics?  In
short, keeping the blade perpendicular at all times will hinder, not
help.

Quote:
>This picture is from their page and proves that (in theory) my new oar
>design would be much better:

Sorry, but it proves no such thing.  Rowing has its share of technical
fallacies & this drawing contains unwarranted & erroneous assumptions of
which "Rudern" should be ashamed.  Whence the idea that the rower always
pulls at 90 degrees to the oar shaft?  In that case rowers would be
always pulling themselves out of the boat.
Do some simple, dimensionally-accurate drawings of real rowing & perform
proper graphical resolutions of forces at different parts of the stroke
& at different parts of the system (include pin, stretcher, wrist,
elbow, shoulder, back, etc).  Yes, you get all sorts of off-axis forces
on the boat but the only ones of prime interest in propulsion (since the
others cancel each other out) are the forces resolved into the direction
of motion.

Now, start with a clean sheet of paper, a sharp pencil, some texts on
fluid mechanics ....

And for those who think fluid mechanics unimportant in rowing:
The difference in windage between a well-designed 2-stay rigger :-) & a
traditional 4-stay rigger is such that, into a 5 metres/sec headwind, a
single with the 2-stay will go 2 seconds/2000 metres faster than the
same single with the 4-stay.  Then add on the difference in splash drag
and the gap widens.  Know another gizmo that'll give you 2 seconds
advantage in half your races and no penalty in the rest?

Cheers -
Carl
Carl Douglas Racing Shells
                    (for AeRoWing low-drag Riggers & Fine Small-Boats)
The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JZ, Great Britain
URL     http://www.rowing-cdrs.demon.co.uk     TEL +44 (0) 1784-456344