A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Michael Bradley
Date: 2019 Feb 7, 04:08 -0800
I'm with Frank, you'll be fine with a micrometer type Davis.
On the subject of reliabilty over the long term - I suggest you avoid an aluminium alloy sextant with an enclosed micrometer worm.
Two of these, apparently identical, were on board the Golden Globe winner's yacht, and they both failed.
Or look at the problem the other way round. Count your present sextant as the best one, but take also a 'JEEP' Davis Mk 111, using vernier technology (as long as it has a proper case). I can vouch for the fact that if the frame of the Mark 111 warps with time or heat, causing it to bind, you can free it by taking a sanding block and some 600 grade abrasive paper to the curved outside of the frame. A smidge of petroleum jelly on and over the mirror adjusting screws as a precaution, a squirt of WD40 if the index pivot sticks. All materials invariably available on a cruising yacht...