Title text:
They're up there with coral islands, lightning, and caterpillars turning into butterflies.
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Source: https://xkcd.com/3135/
this post was submitted on 30 Aug 2025
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Tidal prediction requires a harmonic analysis of observed tides, and its location specific. Not sure how a watch is supposed to do that other than holding a database of tidal coefficients.
This video contains a lot of interesting history of tidal analysis and prediction:
https://youtu.be/IgF3OX8nT0w
There are adjustments you can make on the watch. Requires tables and whatnot. That's why it took me so long to figure out it wouldn't work!