Learnings: Seafaring
In a society with neither maps nor compasses, a sailor needed a keen knowledge of the seascape. There were several ways to acquire this "sea lore." One was through ancestral tradition. Late Iron Age Scandinavians used sailing routes discovered dozens of decades earlier. They passed this knowledge down from generation to generation through an oral tradition. Their maritime expertise was transmitted by word of mouth to their descendants, who secured it by repetition and imitation.
The other way to learn sea-lore was through direct experience. Becoming a sailor required being "in the field" or, in this case, on the boat. Sailors were constantly performing the same shipboard movements and travelling the same routes. Through repetition, seafarers became familiar with the motions of the sailor and of the ship as it navigated different weathers and currents.
This practical style of learning helped sailors gain a much deeper understanding of seafaring than they would have from a theoretical approach.
Here's a beautiful photo of Norway, showing the stunning grandeur of the landscape that flanked Vikings on their way to new and adventurous expeditions.