Weeeel... we're more than a few steps up on medieval tech. For one thing, the game's set in roughly 1899. For another, according to Joseph Needham's Science and Technology in China, clockwork was not as much of a problem as you might think. They've been working on navigational techniques for some time, given that they have to avoid the giant squid that're longer than, ooooh, the largest island of Japan still above the surface of the ocean. True, there are magically tricked-out ships, but most of 'em are under the direct control and command of the Dragon Throne. Other people have to make do. They all use Imperial measurements, though, including references to units of time that no longer actually exist - i.e. the clock is divided into 'glasses' based on the old length of the standard hourglass, which naturally wasn't exactly the same as a regular hour or whatever. The British Ambassador doesn't bother resetting his timepieces when he comes to the Empire; he locks the British ones in a box and takes out his Chinese set, rather than trying to compensate.

As for sextants and related items, they've been working on sighting devices since Zhang Heng got tired of fiddling with his seismograph. This has had some interesting applications in the field of artillery; they're getting very good at targeting. . .