Date: Thu, 18 Feb 1999 20:34:27 -0800
From: Llama <llama@mb.sympatico.ca>
To: baidarka@lists.intelenet.net
Subject: Re: baidarka carving in s
Douglas Ingram wrote:
>
<snip>
> The shape of the vessle is also very important: how the kayak parts the
> water, and especially, how it RETURNS the water behind it. The drag created
> by the water filling in the vacumn behind the passing kayak is greater that
> the resistance of the water having to part at the bow. A clean gentle flow
> al along the length is critical.
Are you suggesting that a fish-form hull has greater speed potential than a
swede-form? Most fish would agree, I am sure. But most Olympic flatwater designers
favor the swede-form. I wonder if there is a difference between operating on top of
the water and immersed in it that would relate to this. Airfoils are all
"fishform," with the widest point typically about one third back from the leading
edge, depending on how far back you want laminar flow to prevail.
Also, can anyone remember the name of the freestyle canoe designer who built some
fish-form boats several years ago? The Proem, I think was one of his designs. He
also held to the idea that the way you replace the water is more important than how
you get it out of the way in the first place.
>
>
> More important than over all length is the concept of skin friction. All of
> the kayaks skin that is exposed ot the water creates drag as the kayak
> passes. It is EXTREMELLY important to have a smooth skin. A rough skin,
> such as that caused by the fuzz of the canvas that has not been well sanded
> during painting, will have far more effect than shortening the LOA. Also, a
> longer canoe/kayak will inherently have moe exposed surface area than a
> shorter one, but will not have any more power to propel it, resulting in a
> slower boat.
>
<snip>
Can you suggest some good <smooth> skin materials? I am presently building a skin
boat with an eye towards speed potential.
Thanks
Jason Elias