"derbyrm" wrote in message
news:kcglf.624312$xm3.226764@attbi_s21...
That's the "Noble System" which was written up as "Bird's Mouth Hollow
Spars" by Aimé Ontario Fraser in Wooden Boat Magazine, July/August 1999

I've an expurgated version of the Wooden Boat article, with photos, that I
prepared if you'd like it. (Aimé spent too may words on social/dining
issues for my taste.) It's a huge file, 16 MBy, and of course it's
copyrighted material.

The scantlings given were, for an 8-sided spar:
Stave width: 0.4 x diameter of spar - taper square edge
Stave thickness: between 0.1 and 0.2 x spar diameter - (bigger for big
boats) (0.2 for spruce, 0.15 for Douglas Fir)

I found a few programs to calculate the dimensions. Although windows
applications, they're only 60kB large. I can mail them to anyone who's
interested.

Meindert