A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Francis Upchurch
Date: 2016 Jan 15, 04:14 -0800
Hi David, just lost the first attempt to email you!
Not sure if you saw my various postings 2009-2013?
I was lucky to find an original 1920s 11A on ebay for about £200 back then (worth a lot more now!) Perfect working order. Just needed replacement of felt friction pads).
Far too precious for the wet bouncing boat, so I built a couple of copies, the first based on Gary's, the second a near perfect , authentic looking replica using scales by Wayne Harrison. Both work perfectly and give 1-2' accuracy.
The precious original occassionally comes out to play in the dry warm cabin of my home study. It's finest hour was a re-enactment of the famous (infamous?) Chichester Tasman sea flight , using the original nav data from his book. Gary did it first and I copied him (thanks again Gary!) . Remarkably, we both got identical results to Chichester!
I now use the Bygrave replica for all my routine LOPs (now also the BN which is faster, easier and nearly as accurate!) . I use the Fuller 2 for lunars etc if they require 4-7 figure accuracy. My latest Mini Fuller 2 is based on the Otis King format and has cosines in red added to the sine scale).
I recommend cylindrical slide rules as easy to build with limited craft type skills and very accurate. I am now looking at the wonderful Margetts tables for lunars. Joy!