The longitude problem: In the AI era, detection is won on facts, not guesses
Brief
For most of the age of sail, a captain could find his latitude in minutes and could not find his longitude at all. Latitude you could read off the sun. Longitude, your position east to west, offered no such trick. Three weeks into the Atlantic, a navigator knew how far north he was and could only estimate how far along he had come. The estimate was often wrong, and wrong on open water means rocks.
After a British fleet was lost on home rocks in 1707, Parliament offered up to 20,000 pounds for anyone who could solve it. The problem was never the ocean Longitude is not really a sea problem. It is a time problem. The Earth turns 15 degrees an hour. Know the exact time at a fixed reference, Greenwich, check it against your local noon, and the gap tells you where you are.
The whole problem collapses to one question.