[Paddlewise] Baidarka vs. Greenland speed (was RE: Foldable Kayak Mail List Announcement (PakboatPuffin branch))

I'm sure the Baidarka would be faster, rounder bottoms and fuller volume
ends underwater would be the major reasons. The Glider's heritage is racing.
The design, like all Seda's sea kayaks, is based on Olympic flatwater racing
kayaks. Olympic kayaks are optimized for top speeds and strong paddlers.
There is a side benefit when using this racing heritage for shorter sea
kayaks because they are the ones most likely to be paddled up against their
hull speed by the average kayaker.
Before designing your racing Baidarka download the design software and drag
prediction spreadsheet from our website and watch what happens to the drag
numbers as you alter certain parameters in the design. We integrated the
programs so this is very easy to do. You will want to also design the
optimum for the speed range you are going to be racing the kayak at.
Basically for a fast kayak you want to keep the wetted surface low (the
software will help you do this) while making the kayak long enough and full
enough ended that it doesn't get trapped by its own waves (hull speed) until
you are pushing it to slightly faster speeds than you are likely to be
racing it at.
The resulting optimums will be different for paddlers of varying strengths
and endurances. I'd guess you'd want a very narrow kayak with a waterline
length in the of about 17 to 18 feet long and a rounded bottom with a little
rocker especially at the bow. Racing kayaks usually have a prismatic
coefficient in the range of .62 to .64. Call me or stop by (or e-mail me
your designs) and I'll critique them for you before you build.

I remember some very "creative" articles George Dyson did for The New York
Times and Sea Kayaker Magazine about bifed bows and whale oils. Later after
some (reality) testing with Greg Barton paddling (as maybe an example of an
average Eskimo) he changed his ideas some and there was a video being made
for the Discover Channel or National Geographic. (It may have been National
Geo. or Discover magazine that had the later article). I think I have that
program on tape. George pretty much disproved his earlier hypothesis with
the tests (as I had predicted), but creative genius that he is, he quickly
came up with some new theories. I videotaped the testing myself as well and
supplied the Glider used for comparisons with the Baidarkas in the tests.

Matt Broze
http://www.marinerkayaks.com



> -----Original Message-----
> From: Rex Roberton [mailto:rexrob_at_mac.com]
> Sent: Saturday, March 03, 2001 11:10 AM
> To: Matt Broze; Paddlewise
> Subject: Re: [Paddlewise] Foldable Kayak Mail List Announcement
> (PakboatPuffin branch)
>
>
> on 3/1/01 4:53 PM, Matt Broze at mkayaks_at_oz.net wrote:
>
> snip
> > took 40 seconds, the 12'6" Miniraid took 45 seconds. The
> fastest fiberglass
> > single sea kayak I've tested on this course (Seda Glider) took
> 34 seconds
> > and the average of 138 fiberglass and plastic North American
> touring/sea and
> > rec. designs I tested was 38 seconds. The 9'8" Stearns K-116
> inflatable (~30
> snip
>
> Matt,
>
> Can you explain a little about why the Seda Glider is faster than
> the other
> sea kayaks you have tested?
>
> Some day I'd like to build another skin boat just for use in local races.
> I'm wonder about the shape, width, and length.  Narrow and
> rounded hulls are
> faster but how do I decide on the length?  How much rocker?
> Which would be
> faster, a modified Baidarka design or a modified Greenland design?
>
> I know you could write a couple books answering these questions, and you
> don't have time for that, but maybe a few comments to cover some
> basics for
> us.
>
> I've always been interested in the speed question on Baidarka vs.
> Greenland
> design.  Certain Baidarka fanatics claim these Aleut boats have an
> advantage.  They quote Captain Cook and other mariners in the 1700's and
> 1800's who wrote about the speed of the Aleuts.  I have a feeling
> the speed
> had as much to do with the physical strength and endurance of the
> Aleuts as
> it did with the design of the Baidarka.  Imagine the result of many
> generations (over several thousand years) who's existence
> depended on a life
> at sea in the Baidarka.  I believe George Dyson wrote an article
> for one of
> the science journals (does anyone have this information? I think it was
> Scientific American) in which he describes the bone structure of
> the Aleut.
> The muscle attachment locations on certain bones in the upper body were
> larger than normal which was an indication of larger upper body muscles.
>
> Well, Matt, if you could at least comment on the Seda Glider.
> Comments from
> anyone else on any of the above would be welcome.
>
> Okay, back to doing my taxes.
>
> Rex
>

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