RE: [Paddlewise] hull speed

Ok,

I did try some equation. I took something like 20 pieces of data that Matt
Broze has in his spreadsheet for different kayaks, picking up both very
short and wide and very long and narrow and many in between, and using the 5
pound drag, I plotted the calculated speed vs the LWL/BWL (length on
waterline vs beam on waterline). A couple of points were off the trend but a
trend could be seen, so I made a linear regression and found the statistical
straight line that best describes the speed versus l/b. Then I found out the
catalog length and beam and plotted them also obtaining similar results. 

The only problem is that the correlation factor was about 0.73 for both
cases, which gives a very large error margin for one specific competitor,
and therefore big injustice could be made using that approach. I agree then,
that the simplistic approach will not work.

Right now, injustice is larger because all boats compete at the same time,
but nobody can argue the results. Your time is your time and that's it. So I
guess the next best thing is to separate the groups according to the simple
rule suggested by the soundrowers organization.

Thanks a lot to everybody for their input. It was very educational.

Best Regards,

Rafael.



 



-----Mensaje original-----
De: owner-paddlewise_at_paddlewise.net [mailto:owner-paddlewise_at_paddlewise.net]
En nombre de Craig Jungers
Enviado el: jueves, 22 de mayo de 2008 11:01
Para: John Winters
CC: PaddleWise_at_paddlewise.net
Asunto: Re: [Paddlewise] hull speed

On Wed, May 21, 2008 at 4:17 AM, John Winters <jdwinters_at_eastlink.ca> wrote:

>
> Unfortunately the answer is no. No matter what simple formula you use it
> will be unfairly punitive  to some and unfairly beneficial to others.
> Resistance is just to complex.


Not only that, but if you do come up with a formula and if the races are
important enough to the racers, someone will design boats that use loopholes
in that formula to gain an advantage. In the 1970s the IOR produced bizarre
hull shapes that were only useful if the boat raced to that rule (which is
no longer in style). And a boat design (or designer) that successfully finds
a rating loophole can become more in demand and therefore more valuable.

Your post described some interesting rating systems that I've never heard of
but the common thread in rating systems seems to be that, just as you say,
no matter what you use someone will gain and someone will lose; and a lot of
them will cheat. It seems that you can't fool human nature.

Thanks for those illustrations. I particularly liked the one where the
leader who rounds the mark first discovers that everyone who was behind is
now in front. Talk about a dis-incentive to be first to the mark.

Craig

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