Single Boat Analysis — your own race, taken apart
One file, one race, every part of it measured: what each tack and gybe actually cost you in metres, how the start went, how the legs compared, and where the tide was running. Upload the file as it comes off your instrument — no export step, nothing to install, and it isn't stored.
Free to use.
What you get
- Every tack and gybe, costedNot counted — costed. Each one is measured against a ghost of your own boat that carried on without turning, and the answer is in metres: two boat lengths, half a length, gone.
- Manoeuvres compared side by sideAll your tacks overlaid on one chart, aligned and rotated so “up” is toward the wind, with a speed and VMG trace through any you pick.
- The startWhere you were at the gun, whether you were over, how long the line took you, and which end was favoured.
- Start replayWatch the approach and the gun back second by second: distance to the line, the countdown, and time to burn — the surplus between the two, the number that says slow down or go now.
- Race replaysThe whole race, the start, each leg and each mark rounding, played back on a wind-up map with your heading, wind angle, VMG and heel at each moment — so the leg where it went wrong is something you watch, not something you infer from a table.
- Live Wind PredictionRead the wind off your own straight-line sailing as it shifts, instead of using one direction for the whole race, and re-run the entire analysis against it. The wind through the race on one chart, and the live bearing in the corner of every replay.
- Leg by legUpwind and downwind legs found automatically, each with distance, duration, average speed, VMG, wind angle and heel.
- Polar diagramYour speed at every wind angle, from your own race — the shape you actually sailed, not a designer's prediction.
- Tidal vectorsThe current across the racing area, worked out from the difference between where the boat pointed and where it went.
How it works
-
Upload the file
A .vkx straight off a Vakaros Atlas, a Velocitek .vtk, or a .gpx / .fit from a watch or a phone. The format is read from the file itself.
-
It finds the race
Vakaros and Velocitek files carry a start-sequence timer, so races inside a longer file are separated automatically. Pick one if there is more than one.
-
Check the wind
Estimated from your own tacking angles when no wind sensor was logged, and yours to override. Everything downstream — which leg is upwind, what counts as a tack — hangs off this one number.
-
Read the debrief
Everything above on one page. Print it, save it as a PDF, or download a shareable copy that opens in anyone's browser with no login.
Single Boat Analysis — FAQ
What do I need to use Single Boat Analysis?
One race file and a browser. It reads Vakaros Atlas VKX and Velocitek VTK files directly, with no CSV export step, and also reads GPX and FIT files from a watch or a phone. There is nothing to install, and the file is not stored after the analysis comes back.
What does "distance lost in a tack" actually mean?
It is the ground you gave up against a ghost of your own boat that carried on without turning. The VMG you were making either side of the manoeuvre is averaged to give a baseline, and the gap between that and the VMG you actually made is integrated from the moment the turn starts until you are back up to it. Averaging both sides rather than using only the approach matters: a wind estimate a few degrees out would otherwise make every tack onto one side look free and every tack onto the other look ruinous.
Can I use it without a start line?
Yes, though Training Session Analysis is the better fit. A GPX or FIT has no start line in it, so the start analysis, OCS check and time-to-line have nothing to work from and are left out rather than shown empty. Everything else runs normally.
Is my race data private?
The file is sent to be analysed and the results come straight back to your browser. It is not stored. A shareable copy is a single self-contained file that you download and share yourself — nothing is published anywhere by us.
Try it with your own race
Sign in, upload one file, and see what each manoeuvre cost you.