A vocabulary of landscape — a landscape of words
1068 entries
wave piloting
Wave piloting is navigating by reading the ocean swell rather than the sky. Swells run in steady directions set by distant weather, they refract around islands and reflect off them, and where two swell systems cross they produce a regular interference pattern. A navigator lying in the hull of a canoe feels the pitch and roll and reads from it both his heading and the presence of land well beyond the horizon.
Etymology
The English term describes the practice; the Marshallese tradition in which it is best documented has its own detailed vocabulary for named swell patterns and for the nodes where they meet. The teaching device is the stick chart, which maps swell behavior rather than coastlines.
Notes
It works in cloud and at night, when the star compass on this site does not, which is why it matters. The physics is straightforward and the perception is not: The reflected swell coming back off an island is a small fraction of the height of the swell that produced it, and picking it out of the motion of a boat is a skill that takes many years and is taught by lying in a canoe with an instructor.