NavList:

Bill,

For the ditch bag I would go with a solar powered calculator with trig functions. The cheapest can be had for a buck at the dollar store. For primary use I recommend the Ti-36X Pro ($15) which can store formulae for calculated altitude and azimuth. The dedicated hand held calculator is less expensive and more robust than a smart phone but will be missing nautical almanac data, rated chronometer, and selected star functions. I carry both a dedicated solar trig calculator and a smart phone (with 12volt plug) in the sextant box. The smart phone gets used 99.9 % of the time.

Greg Rudzinski

From: Bill Lionheart
Date: 2016 Apr 24, 14:24 +0100

I'd be interested in people's opinions on calculators for sight reduction.

If I have a working phone, tablet, Ship's computer running Navigatrix I can use my python ephemeris and compute altitude an azimuth nicely so we are planing for a situation in which the boats power systems have failed completely so I can't charge up battery devices.

Assuming we have an almanac we are looking at a robust way to do sight reduction quickly without tables. I have £10 cassio  high school style scentific calculators. Typically running off long lasting batteries some with a solar panel built in too. So one of these in a waterproof bag has survived our hypothetical  inversion and demasting.  I can use this for the spherical cosine rule.

The crew and skipper are cold tired and wet and slightly mentally impaired by a blow on the head from a soggy volume of Sight Reduction Tables for Air Navigation and a saucepan that came flying out of a galley locker.

So if you reach in to that water proof bag what calculator would you like to find?

Excellent battery life survivability and low cost (this helps as you can have several  identical) are good features but if it was programmable we might be better able to use it when befuddled by cold and trauma. It would have to keep the program in non volatile memory.

[Obviously this follows on from another disaster that disabled GNSS systems. So the hand held GPS in the grab bag is of no help]

Bill