Discussion Forum—A Way with Words, a fun radio show and podcast about language

Have you tried "portulan" on Tom? These were books containing hand-drawn charts and details of routes between ports together with descriptions of harbors and sea coasts. They preceded more modern navigation methods. They are like a compilation of known facts about how to get from one place to another without the most accurate cartography as a foundation. I've heard sailing folk discuss "portulan" tactics or approaches when talking about what we might call "seat of the pants" navigating or "word of mouth" navigating that relied less on technical tools and more on local knowledge.