With no evidence I believe navigation cues were built into the vessel. By keeping celestial bodies aligned with marks on the vessel one can achieve a seasonal calendar as well as documentation on how to modify the configuration for the next leg of the journey.
Source: Have a Pacific art collection, have been to most of the major museums on the subject, interested in sailing, authored some of the Wikipedia (featured) articles on related watercraft.
What I think is interesting is the physical representation of an oral tradition. This is different than writing as employed today.
What I seem to be noticing is that the ancients used calculus all the time but it was the geometric tools that they used.
This gave technology a form.
Arabic numerals made tabular data more useful leading to the more number based tools.
This seems to have removed the form from technology.
It does make one wonder if any ancient sea fearing humans happened to carve a world map into a durable material such as granite which could have survived until the modern historic era. Maybe such a map, or other mythological artifact fueld the Roman idea of Terra Australis Incognita
/End rampant unsupported armchair speculation
https://en.wikipedia.org/wiki/Piri_Reis_map
https://en.wikipedia.org/wiki/Terra_Australis