Fourth Hand - GMT Watch Setter

From the App Store Source

A GMT watch shows three time zones at once. Setting one means putting four hands in the right places in the right order, and most manuals assume you already know how. Pick your zones. The app counts the crown clicks and the bezel clicks for your offsets, then walks you through them a step at a time, against a diagram of your own dial that moves as you work. WHAT YOU GET Hand positions for your zones, to the minute. A crown click count, and a bezel click count with the direction to turn. The clicks it takes to walk the date round on a movement with no quickset. A reading table for the finished watch. THREE MECHANISMS A true GMT, with a fourth 24-hour hand over a 24-click bezel. Three zones. A dive watch with no fourth hand, so the second zone lives on the 120-click bezel. Two zones. A three-hander under a 24-hour ring. The ring counts a whole day and the hour hand laps twice a day, so the scale runs at double speed. One click is half an hour, and a full turn of the bezel buys twelve hours. A half-hour offset lands on a detent, which a true GMT cannot manage. IN THE APP A spoken guide, for when both hands are on the watch. A bezel that turns under your finger, with a detent you can feel and hear. Fifteen dials. No account and no network. The app collects nothing.

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