The Kayak Forum is Sponsored By
|
|
|
| |
Kayak and Canoe Design Bulletin Board
Re: Eskimo rules for design.
Posted By: John Winters In Response To: Re: Eskimo rules for design. (The Big Legume)
Date: Thursday, 20 May 1999, at 8:03 a.m.
(SNIP)
> There seems to be some speculation, and maybe more basis than that, that
> the Inuits did use a body-part based measuring system. What is valuable to
> us is to try building boats as we think the Inuits might have. We may find
> out that when we apply Inuit rules to European bodies we get poor results.
> Or we may find out that we get good results.> This is a valuable exercise, because if we do get good results, it tends
> to confirm that our speculation may have some basis in fact. It also
> broadens our horizons by allowing us to look at the building process in a
> way that our modern rules don't always allow.I had this very concern when I started looking into this. Because body parts do not scale uniformly (A good source on this comes from the OSHA draft ergonomic standard as well as various ergonomics texts) we can see rather easily that the same ratios used by a particular Inuit won't produce a "similar" (geosim) boat. The biggest variation has to do with weight which does not scale well with height or other body dimensions.
One must also keep in mind that the various components of resistance do not vary at the same rate as body parts nor does controllability vary uniformly with length or beam.
As Nick points out we have no idea what the original builder tried to achieve or even if he thought he achieved it. Thus we have no way to know if using the same anthropometric ratios will produce an equivalent boat or even if the boat had any value in duplicating.
Building true geosims involves some math that anthropometric measure doesn't provide.
Actually our modern methods of design make designing to fit a particular person much more precise since we can specific characteristics around the person's weight and dimensions - something anthropometric measure cannot do well.
Building boats using the anthropometric measure system may or may not produce a useful boat and so may not produce a lot of information. Clearly the Inuit (even within a particular region) used no fixed set of ratios. We can get a hint of what happens when an Inuit builder built boats for Europeans by looking at the boats used by the British Arctic Air Route Expedition. Compare, for instance, Quentin Riley's boat (bKr-12) (built originally by the Inuit builder for himself and sold to Riley) with W.E Hampton's kayak (bKr-17)(built by the same builder for Hampton (not perfectly sure of this but lots of evidence of it). John Brand, who made some replicas concluded that "the succesful adaptation of the Greenland kayaks (was) impossible". I don't fully agree with that since the poor results may have stemmed from the use of anthropometric sizing rather than the proper method of creating a geosim. I am incluidng the proper method in my book which should help builders of replicas.
I have finished the studies of the boats I planned on putting in my book but the temptation to add more nags me.
Cheers, John Winters
| |
Kayak and Canoe Design Bulletin Board is maintained by Nick Schade - Guillemot Kayaks with WebBBS 5.12.
|
Boat Design |
|
|
|
