Guide

How to analyse a sailing GPS track after training

A useful sailing GPS review is not just a speed trace. The goal is to turn position, heading, timing, and weather context into a short list of decisions for the next session.

Takeaway 1

Start with a clean GPX, FIT, TCX, or KML export so the review is based on the actual sailing window.

Takeaway 2

Use speed, heading, and point-of-sail changes together instead of treating each metric in isolation.

Takeaway 3

Compare similar legs and conditions before deciding whether a change came from technique or weather.

Start by checking the shape of the track

Before looking at averages, inspect the route shape. A clean track should show the launch, sailing area, manoeuvres, and return without long gaps, duplicated points, or shore-side movement that was not part of the session. If the file includes rigging time, towing, or a watch left running after sailing, trim the review mentally or in the source system before comparing results.

The route shape also tells you whether the session has enough comparable work to be useful. Repeated windward legs, downwind runs, or drills around a fixed area are easier to compare than a mixed cruise with constantly changing objectives.

  • Check for GPS dropouts or straight-line jumps between points.
  • Separate actual sailing time from launch, recovery, and drifting.
  • Look for repeated legs that can support fair comparisons.

Read speed with heading and wind context

Peak speed is rarely the most useful number on its own. A short burst on a reach can hide poor upwind VMG, inconsistent tacks, or slow acceleration after manoeuvres. Better reviews connect speed to heading and point of sail so you can see where pace was gained or lost.

Weather context matters because the same boat speed can mean different things in different breeze. TillerWise enriches sessions with weather context so sailors can review whether a change in pace likely came from execution, wind strength, or direction shifts.

Turn the review into a training decision

A strong post-session review ends with one or two actions, not a long dashboard screenshot. After checking the map, speed trace, manoeuvres, and VMG, write down the highest-leverage pattern to repeat or fix. That might be preserving speed through the final third of a tack, holding a steadier upwind angle, or comparing downwind mode choices in similar breeze.

Saving those decisions across sessions makes the data useful over a season. The value compounds when each track becomes a reference point for the next session instead of an isolated activity file.