How to analyse a foil session: from track to next session

Foiling is a game of momentum. A small error in trim, board pressure, wing position or line choice can end a long flight. You can feel efficient and still be overworking through transitions, or think a line was clean and later find your speed dropped on every turn. That’s why a map and a max-speed screenshot aren’t enough.

Start with the session story

Before opening the charts, replay the conditions: what was the wind doing, was the water flat, rolling or crossed up, what gear did you ride? Then follow the rhythm of the ride instead of jumping straight to your personal best.

1. Takeoffs and early flights. The first minutes show whether setup and body position were working. Repeated short tracks, abrupt speed drops or long gaps before consistent flight point to trim, power, pump timing, foot pressure or line choice.
2. Your best runs. Find where your top speed happened and compare it with the runs around it. Different angle? Flatter water? A gust?
3. Where momentum disappeared. One transition turns into a touchdown, a recovery and a restart. The track shows where that pattern repeats.
4. The final runs. Did pace or control fade late? That’s endurance and pacing, not technique.

The core metrics

• Foiling efficiency: how much of your moving time you spent flying rather than slogging, pumping back up or resetting. See Foiling efficiency and airtime.
• Speed, through three lenses: maximum (your fastest moment), average (the whole session) and sustained pace over 10 or 30 seconds (usable speed).
• Distance and moving time: workload, separated from setup time, breaks and time on shore.
• Tacks, gybes and transition quality: count them, then look at speed before, during and after each one.

Eight analysis examples

1. Top speed vs sustained speed. A high peak with a modest sustained pace means you overpush in short sections and give it back in recovery.
2. Efficiency across the whole session. A strong session isn’t only about how fast you went, but how much of it you spent flying cleanly.
3. Gybes beyond completion rate. A landed gybe is good, a fast one is better, a repeatable one that keeps speed is real progress.
4. Tacks in changing conditions. Tacks expose timing, apparent-wind management and confidence. Compare them in steady and gusty sections.
5. Line selection. The fastest-looking run isn’t always productive. Compare upwind progress, not just speed (VMG analysis is in Waterspeed Ultra).
6. Equipment changes. New front wing, mast length or stabiliser? Memory is biased. Compare sessions in similar wind and water, one change at a time.
7. Consistency, not just personal bests. One PB can hide a messy session. Tightly grouped speeds and more stable flight times mean performance is becoming reliable.
8. Local patterns. Over time your log shows which spots, wind ranges and times of day suit you, which helps you choose when to go.

Read the track like a coach

The GPS route is a record of decisions. Straight, consistent lines show efficient upwind work. Wandering lines, early bear-aways and wide turns show where you lost ground. Overlay speed on the track to see where flight broke down.

Compare like with like

A 25-knot flat-water session shouldn’t be judged against a light-wind, rolling session on a bigger foil. The numbers may look worse even when your riding improved. Group sessions by spot, wind range and setup before comparing.

What GPS can and can’t tell you

GPS is an excellent training tool, but track quality depends on device placement, reception, recording interval, pauses and water movement. It may not interpret every touchdown or pump perfectly. Treat brief spikes that don’t match how the ride felt with caution.

The tools that help

• A watersports tracking app for speed, distance, route, runs and transitions, without an instrument stack on the board.
• A watch or marine display for quick feedback between runs: time, speed, distance.
• Video from a stable point: GPS shows the outcome, video shows the movement that created it.
• Weather and water data (wind models, gusts, swell, tide) for context. Forecast apps such as Windy, PredictWind or Surfline, and charts such as Navionics for long or coastal routes.
• On-board sensors for advanced tuning of mast position, shims or wing size.
• A short log: one win, one problem, one focus.

A general fitness tracker still has a place for heart rate, sleep and training load across sports. Many riders use both: the fitness app for the broad picture, a watersports app for the details of their water time.

A five-minute review routine

1. Open the session while the conditions and sensations are fresh.
2. Check the headline numbers, then find your best run or cleanest section.
3. Find the one place where momentum disappeared most often.
4. Write a short note: date, spot, discipline, gear, conditions, one win, one problem.
5. Choose one goal for next time, specific enough to notice on the water: longer flights, more clean gybes, better pace on the last runs.

Log the average days too, not just the best ones, or your history gets distorted.

Safety is part of performance

Foiling takes you farther from shore faster than many riders expect. Use live location sharing on long downwinders and unfamiliar spots, and never let numbers push you to extend a session beyond your margin.

The point isn’t to turn every launch into a test. But when you capture the right details, the feeling of a great run doesn’t disappear at the beach.

For turns specifically, see How to improve your jibes with GPS data.