A crossing is already a chart

Every other sport in this shop is having its routes drawn for the first time. Sailing is not. People have been putting passages on paper since long before anyone thought to record a bike ride, and the conventions are old enough to have become taste.

Which is why the second verb here is borrowed from another discipline's vocabulary. It is the only one in the whole system that is, and it earns it.

Tacking is the whole picture

A passage recorded under sail looks nothing like a passage motored. The zigzag of beating to windward is the single most distinctive shape any GPS produces — a sawtooth that no road, trail or river would ever make.

It also carries information. The angle of the tacks tells you how close the boat pointed. The length of each leg tells you how much sea room there was. The place where the sawtooth stops and the line goes straight is where the wind went aft, and every sailor reading the print will find that point without being told.

What to leave off

The temptation is to add the coastline. Resist it for a crossing.

An offshore passage drawn against a map becomes a small line in a large expanse of nothing, and the tacking detail — the actual subject — shrinks to invisibility. Print it clean, at a scale where the sawtooth is legible.

Coastal passages are the opposite case. A route threading between islands makes no sense without the islands, and the street-map treatment earns its place.

On distance

Sailing produces long tracks at low speed, which means a lot of points. That is good for detail and hard on file size — a multi-day passage can run to a hundred thousand recorded positions. The drawing simplifies to what the paper can resolve, which is roughly a thousand points at poster size. Nothing you would see is lost; the file just stops being unwieldy.