From: "John Winters" <735769@ican.net>
To: <baidarka@lists.intelenet.net>
Subject: Re: baidarka swedish fish revisited
Date: Thu, 4 Mar 1999 06:49:55 -0500
Skip Snaith wrote;
(SNIP)
>Up here in Chevak, qayaq # 2 of the Bering sea type is being honcho'ed
>by an elder(he's nearly 80). This boat is certified traditional. The
>maximum beam is located aft of the centerpoint, and extends from the
>cockpit aft. The cockpit too is slightly behind the centerpoint.
Does this refer to the center of the waterline length or overall length?
>In numbers, if you measure 4 feet back from each end, the beam at the
>after location is fully 2 inches wider than the fwd one.
The center of buoyancy and its relationship to the waterline length
normally determines "form" (fish vs Swede) although many people assume that
the center of flotation serves as the determinant. In several lines
drawings of Greenlandic origin (John Brand, Eugene Arima etc.) the center
of flotation lies forward of the midpoint while the center of buoyancy lies
aft.
>He was quite insistent about this, citing that most of the loading is
>carried in this area. Makes sense for handling. Note that SPEED was
>not a design issue in this matter (at least as far as I am able to
>ascertain).
The cockpit location (and the corresponding concentration of weight) has a
large effect on the center of buoyancy since the boat will trim
accordingly. Whether the trim adopted by the boat produces the best
performance (handling and speed) depends upon the resulting shape. In
simple terms, moving the cockpit forward or aft on the same boat might
alter the boat from fish to Swede form since the boat trims accordingly.
The resulting CB may or may not conform to the location of the largest hull
section.
Sorry I missed this discussion earlier.
Cheers,
John Winters
Redwing Designs
Specialists in Human Powered Watercraft
http://home.ican.net/~735769/