OpenWater - Water Speed
Health & FitnessSports

OpenWater - Water Speed

Laan Labs · released 15 Aug 2026 · Open in App Store ↗

Revenue 30d not estimated
Downloads 30d not estimated
Rating 5.00 3 reviews

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Description

openWater is a GPS speed and technique tracker for wingfoiling, parawinging,

downwinding, windsurfing, kitesurfing and sailing. It is open source, works

entirely offline, and never asks you to create an account.

RECORD ON YOUR WATCH OR YOUR PHONE

Start a session in one tap. The Apple Watch app runs standalone — it does not

need your phone nearby, or even installed. Water Lock engages automatically,

and the session keeps recording with the screen off and your wrist down. Your

track is written to disk continuously, so a flat battery or a crash costs you

seconds, not your session.

Seven live screens: speed, splits, session totals, wind angles, foil time,

controls, and a racing start countdown you can sync to the committee boat's gun.

SPEED, MEASURED PROPERLY

Every category the speedsurfing community actually uses:

2 second peak

Best 10 seconds, and the average of your 5 best 10-second runs

100 m, 250 m, 500 m, 1 km, 2 km, nautical mile, 5 km, 10 km

Alpha 500 — a 500 m run with a gybe, finishing within 50 m of its start

30 minute and 1 hour averages

Any custom distance you add, applied retroactively to sessions you already

recorded

These are computed on the continuous track rather than snapped to the nearest

GPS fix, because a single second of slop is ten metres at twenty knots. Speed

comes from the receiver's Doppler measurement, not from differencing positions.

SEE WHAT ACTUALLY HAPPENED

An hour of winging in a bay is forty passes through the same water, and drawn

as one line it is unreadable. openWater fixes that:

Flights are drawn bold, slow sections fade back, falls get a marker

Pick any single run and the other thirty-nine drop away

The Runs view drops the map entirely — one lane per run, stacked in time, so

nothing overlaps. It reads top to bottom like a score.

Replay the whole session with a playhead, speed heatmap and live readout

FOR FOILERS

Time on foil, number of flights, longest flight, takeoff speed

How long your pump-up takes

Falls counted separately from touchdowns, because they are not the same thing

Longest clean run — the metric that keeps improving long after top speed stops

FOR WING AND PARAWING

Wind direction worked out from your own track, with no weather service and no

internet needed

Polar curve, VMG upwind and downwind, tacking and gybing angles

Gybes and tacks detected and scored: entry speed, minimum speed, recovery

time, and whether you stayed on the foil

Port versus starboard comparison, so you can see the side you have been

quietly avoiding

FOR DOWNWINDING

Glides detected from the pump-and-glide rhythm

Glide count, longest glide, and what share of the run was on foil

How often you linked to the next glide without dropping

The swell period you were riding

YOUR DATA IS YOURS

Import GPX, TCX, FIT and CSV — Garmin, Coros, Suunto and most apps

Export GPX, TCX, CSV, GeoJSON, or a complete lossless archive

No account, no server, no tracking. Nothing leaves your device unless you

send it.

Sharing trims the start and end of your track by default, because those are

usually your car or your home