A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2017 Aug 24, 13:52 -0700
Is there a nautical slide rule or E-6B-ish tool available? I have tried to find one myself, but without success.
Get hold of a couple of old E6s or similar (the RAF Mk4Bs are best), preferably one should have a square grid on part of the slide. On the divergent slide, get some typists correction fluid and white out the last nought on the speeds. This will be great for tidal flow triangle of velocity problems. On the one with the square grid on the slide, white out every 30 degrees on the rotating azimuth ring, and draw in hours one to 12 instead. Rotate the disc until time of high water is at the top. Place the mean height of tide under the central dot and mark half the range on the plastic. Turn the disc until the actual time is at the top and you have the height of tide according to the rule of 12ths. In the photograph, I've substuted a Mears Slide, but the principle is the same. Don’t use your best E6; save that for aeroplanes. DaveP