00 vs OpenWater
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
00
This workout tool allows you to create custom exercise routines with timers, reminders, and notes. Track your progress by saving sessions and viewing your improvements over time. It's a free, personal project designed for users who know their own exercises.
- Customizable exercise display
- Metronome and reminder setup
- Exercise tagging and notes
- Create sets and routines
- Save and track session progress
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00:37 is a workout tool. important notes: - the app doesn't contain any exercises or routines. add and do exercises you know how to do properly. 00:37 does not replace a mentor or classes. - the app is a side project, mostly designed for personal use, made available for free. I may update it occasionally, but don't expect regular updates or convenient features. I may also remove features that don't work for me or change things in ways you may not like; that's part of the deal here. features: - 5 types of exercises display time, repetitions, or amounts in different ways. - add a metronome, setup time, reminder sounds, tags, and notes to your exercises. - create sets and routines of exercises. - save your sessions so you can see how you progress. tip: - you are less likely to miss a timer, break, or reminder by going to Settings > Notifications > 00:37 and setting the notification style to 'Persistent'.
OpenWater
Track your speed and technique for various watersports using GPS. This open-source app works offline and offers detailed performance metrics for wingfoiling, kitesurfing, and more. Analyze your sessions with advanced visualization tools.
- GPS speed and technique tracking
- Offline functionality
- Standalone Apple Watch app
- Detailed speed metrics
- Session visualization tools
- Data import/export
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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
Screenshots
Verdict
The clearest difference is update cadence: 00 at daily against OpenWater's every 4 days. 00 also leads on iOS requirement (10.0 vs 18.0). OpenWater's advantage is device support (4 vs 2) and ratings volume (3 vs 1). On price, rating, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for 00 against 5.0 for OpenWater. Both are backed by a comparable volume of ratings — 1 and 3 respectively.
00 ships an update daily, OpenWater every 4 days. The most recent releases landed on September 19, 2026 and September 18, 2026 respectively.
| Parameter | 00 | OpenWater |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) | 5.0 (3 ratings) |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 1 | 3 — better |
| Update frequency | Daily — better | Every 4 days |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad, Apple TV, Apple Watch — better |
| Requires iOS | 10.0 — better | 18.0 |
| Further details — not scored | ||
| Size | 28 MB | 22 MB |
| Age rating | 4+ | 4+ |
| Developer | Adriaan de Jongh | Laan Labs |
Customer experience
00
OpenWater
In-app purchases
00
No in-app purchases
OpenWater
No in-app purchases









