Re: [Paddlewise] Rudders redux

A couple of items.

On 6/29/07, John Winters <jdwinters_at_eastlink.ca> wrote:

 Suitable objective testing to support these
> arguments would go a long way and be enormously useful.


"Suitable" is the operative word here. Short of putting a paddler in a suit
that has been completely set up to measure effort (strain gauges everywhere
I suppose), and into a kayak that has been prepared the same way, I can't
think of a way to do "objective testing".

And anyway, what constitutes objecting testing? Many of us seem to feel that
the only objective results can come from some form of test. But for a long
time scientists had only empirical evidence to use. Biology, especially, has
been built on a foundation of empirical (observed and recorded) evidence.


> Of course, the opposing side isn't any better. Paul Caffyn is a good story
> but his story is anecdotal and only applies to him and his particular
> experience.


Caffyn's story is only "anecdotal" in the sense that he was not a trained
scientist and the data was not the focus of his efforts. If, as I understand
it,  he kept a daily log with miles covered and hours paddled that
stretched over years then that would be empirical evidence. Anecdotal
evidence is more closely associated with patient reports of the side effects
of drugs or hearsay. Caffyn's logs would not be considered anecdotal in that
sense. Now if he said, "I'm pretty sure I paddled farther with a rudder than
without one" then *that* would qualify as anecdotal evidence.

Nor would Matt's evidence, which is essentially in the same form but more
detailed, be considered anecdotal. Matt's records, like Caffyn's form
empirical evidence which can be reduced to statistical evidence by careful
anaylysis.  Any careful record of results gathered over a long period of
time would not, in my opinion, be considered anecdotal even when collected
by a "non-scientist".

Once you have enough empirical data (the numbers of bird species inhabiting
one area every December times the number of areas under observation times
however many Decembers this happened, for instance) you can then reduce that
to statistical evidence.

Paul Caffyn's records gathered over thousands of miles of paddling over
several years would be no less anecdotal than the annual bird count. And,
just as the decline of a species over time can be documented this way, so
can an increase of miles paddled after a modification to the same vessel.

Caffyn's records obviously apply only to him, his boat, and his experience.
But the statistical differences seem to be clearly caused by the
modifications to the boat. Certainly Caffyn thinks so. Now, if we had 4 Paul
Caffyn's paddling 4 different boats under similar conditions for the same
period of time, then that would allow us to compare the results.
Unfortunately, we only have Paul Caffyn. But his empirical records lead to a
compelling statistical result: He covered more miles in less time with a
rudder than without.

It is certainly not a universal recommendation for rudders.


Well, it says nothing about how a rudder would help someone in a rock garden
or surfing but it's certainly evidence that for point-to-point paddling the
same boat paddled by the same person can go farther with a rudder than
without.  And it's not anecdotal.


> Obviously the personal preferences of paddlers are just that - personal,
> and most arguments in favour of rudders hinge on personal preference. Like
> the opposing view they lack objective support.


Actually, this is not the case. Empirical evidence collected by an expert
(does anyone think Paul Caffyn is not an expert paddler?) is considered to
be objective; partly because it can be repeated. All you and Matt have to do
is, say, paddle around Australia in any boat you choose. Paddle half way
without a rudder and half way with a rudder. Keep a record of how far you
went every day and how long it took. At the end we'll have a much better
picture of whether a rudder is helpful for point-to-point paddlling.

However, because there is so much support for Richard's points they are
> useful. Most designers of sprint kayaks actually do the research... (but)
> ...as Matt points out, the (sic) seem specific to one type of boat in very
> specific conditions. It would be good to have data that crossed those
> boundaries.


We do have data that crosses those boundaries. Paul Caffyn's data. I'm not
sure why you so casually dismiss it.


Craig Jungers
Royal City, WA
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