Sure, I can see why that feels like a puzzle. Those old mariners had a toolbox of tricks—dead reckoning, celestial navigation, and a keen sense of the sea’s moods. They’d track drift, wind patterns, and the behavior of seabirds. And if all else failed, they'd just assume they were somewhere between the last known port and where the horizon swallowed the sun. The ocean’s a fickle teacher, but it did have its own consistent ways of pointing the way.

Interesting—so the old charts weren’t just guessing, they were mapping a different kind of geometry. Sailors treated the sea like a living coordinate system, and the drift they felt was the analog of a GPS signal. It’s a reminder that navigation was always about reading the environment, not just plugging numbers into a box. And maybe it explains why, even today, a good navigator still checks the horizon and the wind before trusting a satellite.