The best replacement for chronometer is chronograph.

The best alternatives to chronometer are rated as following:
★★★★★  chronograph
★★  myfitnesspal
★  chronometre
  superlative chronometer

Your alternative for chronometer is not listed? Suggest!
Speaking about chronometer, one probably shouldn't forget about longitude.

Other search terms related to chronometer and their ratings are:
★★★★★ longitude
You have in mind a companion for chronometer and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of chronometer in all years. Click on graph for more.
chronometer
chronograph
myfitnesspal