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Re: Kayak design article in Scientific American
By:Nick Schade - Guillemot Kayaks
Date: 3/24/2000, 11:20 am
In Response To: Re: Kayak design article in Scientific American (Paul G. Jacobson)

I would not sell the Aleut and Inuit short. They are just as capable at looking at boat and seeing things that could be improved upon as we are. If the were rigorously following animal example their boats would be quite different. Animals have ribs running transverse too their length. It skin-kayaks were built this way the skin would dimple in between each rib, creating a very inefficient shape.

The original kayak buildes put in stringers running the length of the boat. This makes the dimples around the stringer run lengthwise - much better.

I think we can be pretty confident that paddlers spent a lot of time looking at their boats move through the water and if the noticed anything that looked "funny" they would try to do something about it.

I don't think much on a kayak is an "accident" any more than it is an accident that automobiles have rubber tires. They used the materials they new about and could put their hands on and did what they thought was best. It is possible that some times they were wrong or that some idea had an unexpected consequence, but the truly "bad" ideas would tend to get weeded out and the "good" ideas would be usually get incorporated in future boats.

They probably worked in much the same way we do today, they just had a different set of tools and materials to work with.

> I have a hunch that some of the attributes of skin on frame design are the
> result of cumulative lucky coincidences more than rigorous design.

> If the origianl kayak builders were emulating large sea mammals, like
> whales, seals and walruses -- and using the bones from these animals as
> components of their crafts, then a good deal of the design would be
> determined by the materials at hand. If you use the ribs from a walrus as
> the ribs of your boat then you can hardly take credit for the curvature.

> Many years ago I saw an exhibit on soap bubbles in a mathematics exhibit
> at the local museum. One of the points being made was that the soap film
> would follow the shortest distance between all the surrounding points. Dip
> in the plain, circular bubble wand and you get a plane. Dip in a 3-D wire
> frame, and you get an interesting shape. I think that with the Inuit
> kayaks, the flexibility of the skin would allow it to work like a stiff
> soap film. when the boat was placed in the water the pressures would bend
> the skin into a concave shape on each side of the boat. Like a soap film,
> this shape should be close to the minimum size needed. That would mean a
> minimum wetted area, and a minimum of drag. The effect of having the left
> and right sides being convex, from keel to the edge of the bottom, should
> give a nice skeg-like effect, which would enhance tracking, too.

> Strangely, when I read about design specs for skin covered boats they
> mostly seem to assume that the hull material is rigid. I'm not sure what
> kind of fudge factors are involved, but the skin DOES flex once the boat
> is in the water and the paddler gets in the boat -- and that absolutely
> changes the underwater shape of the boat, so either the performance is
> going to change from the design specs, or you have to rethink whether the
> ideas behind the design were valid in the first place.

> This whole thread should probably be in the kayak design area.

> Just adding my 2 cents.

> Paul G. Jacobson

Messages In This Thread

Kayak design artical in Scientific American
Chris Menard -- 3/20/2000, 7:51 am
Re: Kayak design artical in Scientific American
lee -- 3/21/2000, 9:23 pm
Re: Kayak design artical in Scientific American
Nick Schade - Guillemot Kayaks -- 3/22/2000, 9:45 am
Re: Kayak design article in Scientific American
Paul G. Jacobson -- 3/23/2000, 10:17 pm
Re: Kayak design article in Scientific American
Greg Stamer -- 3/25/2000, 9:13 am
Re: Kayak design article in Scientific American
Nick Schade - Guillemot Kayaks -- 3/24/2000, 11:20 am
Re: Nick
lee -- 3/22/2000, 10:44 pm
Skin boats
Nick Schade - Guillemot Kayaks -- 3/23/2000, 10:01 am
Re: Kayak design artical in Scientific American
Chris Menard -- 3/22/2000, 7:46 am