Subject: Re: [baidarka] Kayak to Human Scaling
From: wolfgang brinck (nativewater@yahoo.com)
Date: Thu Nov 01 2001 - 16:29:17 EST
A few things to keep in mind:
If you are tempted to change the design of a boat, be
aware that linear scaling may not produce linear
changes in performance.
If you feel that you need more room in a boat, try
elevating the deck rather than increasing depth below
the gunwales.
Boat measurements in terms of human body parts are
after the fact recordings of good design and don't
necessarily transfer from the original kayak culture
to ours unless you are built like an Aleut of old.
Generally, people in the Arctic had shorter arms and
legs relative to trunk size than modern Americans and
Europeans. Our centers of gravity when sitting in a
boat tend to be farther forward. So in general we need
bigger cockpits placed a few inches farther back than
the original boats.
As for what boat to build, I think that in general,
baidarkas are a better choice for large people than
Greenland boats. Greenland gunwales start going convex
at about the point where a tall person's feet would
be. This necessitates moving the inflection point
forward or making the boat longer. The baidarka
gunwales by comparison are convex throughout and can
therefore accomodate a large paddler with less
violence to the basic design. I would say that in
general, first time builders should stay close to a
traditional design and get some experience in the
water with how form affects function before proceeding
on radical modifications. Or take the rough prototype
approach that Peter outlined on this list.
One final point. The Shields replicas are based on a
drawing rather than an actual boat specimen. The
Shields replicas I have paddled tend to be tippier
than replicas based on baidarka specimens collected
more recently.
Wolfgang
--- Juan Ochoa <jochoa@ll.mit.edu> wrote:
> On Monday evening, I got a chance to try Kirk's
> Shields baidarka. It was an
> enlightening, but thankfully dry, experience. After
> about two minutes of
> managing to stay upright, I thought, "To hell with
> the baidarka idea, I'll make
> a Greenland kayak. At least I know how to paddle
> one of them". I continued
> for an hour until I got more comfortable paddling
> and darkness came.
>
> It was very useful to find out I have become very
> used to a low rear deck and
> side coaming. I can also see, one can get used to a
> much lower secondary
> stability, but it will require a fair amount of
> attention to staying upright.
> I will probably persist and learn. My wife had a
> easier time in the baidarka,
> because she is smaller and had a lower center of
> gravity. I could even notice
> the difference between having my legs flat and
> pulling my knees up to brace.
>
>
> It occurred to me, that we as a group are enchanted
> with the idea of making
> exact replicas of these wonderful craft. The
> problem, at least for me, is that
> I'm 6'2", 184 lb., with a 34" inseam, size 11 feet,
> and I'm trying to fit in a
> kayak designed for much smaller people. My guess is
> that Harvey is more
> successful with his reproductions because he is of a
> size similar to the
> original designers.
>
> Has anyone encountered some data as to the size of
> the Inuits or the Aleuts
> that built these boats which we are now copying?
> That way we could scale the
> original designs to fit. What about the
> anthropomorphic measurement system for
> scaling the kayak to the paddler? That seems to
> work just fine for the
> Greenland paddles, but what about the whole kayak?
>
> John was right, this is the hardest part of the
> process. Which kayak do I
> build?
> ______________________________________
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