Field notes 4 MIN READ
A crossing drawn as it happened
The gap between the course you plotted and the track you sailed is the whole print. Nothing else in navigation shows the wind so clearly.
Sailing is the sport where the plan and the record differ most, and where the difference is the most interesting thing about the file.
The plan is a straight line
A passage plan is waypoints. Straight legs between them, chosen for safety and distance.
The track is what the wind permitted. Upwind you cannot sail the straight line at all, so you zigzag; downwind you may sail deep angles for speed. Current sets you sideways for hours. Weather routes you around a system.
Print the track, and the plan is visible by implication — the straight line between the ends that nobody sailed.
Tacks are the drawing
A beat to windward produces a sawtooth. Each leg is a tack, each corner is a manoeuvre, and the angle between them is your boat's real tacking angle on that day in those conditions.
That is not decorative. Somebody who sails can read the wind direction off the drawing, see where it shifted, and find the tack that went on too long.
Nothing else we print carries that much recoverable information about conditions.
Where the file comes from
A chartplotter is the best source. Fixed antenna, clear view of the sky, consistent logging. Most export GPX to a memory card or over an app.
A watch works and is noisier — a wrist under a jacket in a cockpit does not have a good view.
Either way, elevation is meaningless. Turn the profile off; a boat at sea is at sea level, and what a barometric altimeter records on a passage is the weather, which is a different and worse print.
A season rather than a passage
Layer every trip from one season and you get a cruising ground: the routes sailed repeatedly go dark, the one long passage stays faint, and the shape is of where a boat actually goes rather than where it went once.
For most sailors that is the more accurate portrait, and it needs 70×100 to read.
Questions people actually ask
- Can I use a track from my chartplotter?
- Yes. Most plotters export GPX, and a plotter track is usually cleaner than a watch because the antenna is fixed and has a clear view.
- Should I print the plan or the track?
- The track. A plotted course is a straight line between waypoints; the track is what the wind allowed, and the difference between them is the passage.
- Do the tacks show?
- Yes, and they are the best part of the drawing. A beat to windward appears as a zigzag whose angles are your boat's actual tacking angles.
- What about a whole season?
- Works well. Layer every passage from a season and the picture is of a cruising ground rather than a trip.
YOURS, FROM A FILE, IN 90 SECONDS
One effort. One sheet of paper.
Bring the file and every choice is yours: treatment, colour, which numbers come along. Museum-grade 250 gsm matte, printed in Denmark, shipped in a tube with a nail taped inside.
Print it. FROM 349 kr