Message-Id: <199811061327.IAA01965@mailhost.capecod.net>
From: "William H. Low" <billow@capecod.net>
To: <baidarka@lists.intelenet.net>
Subject: Re: baidarka FOLDABLES AND STIFFNESS
Date: Fri, 6 Nov 1998 08:27:18 -0500
I've built several with split or articulated keelsons. I used polyethylene
sheeting in a joint similar to Zimmerly's picture. The joint worked fine
but I did not find any improvement in performance and over time the lack of
rigid support of the keelson stressed the ribs and the depth to shear
became less. The boat is more flexible in waves but does not seem to
improve performance over a rigid keelson. As far as I'm concerned it was a
failure and I would not bother to do it again.
Bill
----------
> From: Robert Morris <brewerycreek@hotmail.com>
> To: baidarka@lists.intelenet.net
> Subject: Re: baidarka FOLDABLES AND STIFFNESS
> Date: Friday, November 06, 1998 12:05 AM
>
> One of the unique aspects of the Aleut boats was the ivory and bone
> bearing surfaces in many of the joints. The function of these may have
> been to stop the creaking of the joints as the boat worked and so avoid
> startling prey. I believe that they were used at least in part to
> improve mobility in the joints. There were short strips inlaid in the
> deck stringers and deck beams where they met, in between the halves of
> the bow and stern cross pieces, and a complex sliding ball and socket
> joint in the keelson joints. The shapes of the keelson and bow and stern
> joints seem to control the shear in the joint along one axis. Good Idea.
> If you are going to build a flexible boat it pays to have it flex along
> your intended direction of travel.
>
> After having built several dozen baidarkas, I am experimenting with two
> baidarkas now using UHMW plastic as a low friction bearing surface in
> the bow and stern and deck stringer joints. I am still trying to figure
> out how to machine the stuff with my resources to make effective keelson
> joints.
>
> Refer to Qajak by David Zimmerley or to Contributions to Kayak Studies,
> edited by E. Arima.
>
> Robert Morris
>