A bit LARPy, I would think. The need for ludicrously accurate marine chronometers is doubly obsolete because of the somewhat lessened need for celestial navigation and the fact that the GNSS systems also disseminate the time (in fact, this is the only thing they can do). Even for those obligated to practice celestial navigation, pretty much any old quartz watch will do the job and you can check/set them by WWVB.
It's a genuine question about the conditions under which error bar performance was claimed (by whomever you quoted).
> A bit LARPy, I would think.
That's all relative - I worked global exploration geophysics for a decade, worked with folk that developed sapphire oscillators for use in gravitational wave detection, dabble with SKA data, etc.
Even the cheapest quartz watches (0.5s/day) are significantly more accurate than a typical Rolex (2s/day) in normal use.
I'm having some difficulty understanding how g shocks, temperature variations, and barometric changes will have less of an effect on a fragile mechanical system than a tuned electronic one.
