crazyDive is a dive and snorkel logbook. Your Apple Watch records the dive for you — depth, water temperature, GPS position at the surface and, if you want, compass and motion — and your iPhone keeps it with its profile, its map and the weather at the time.
| Device | What you need |
|---|---|
| Apple Watch | A model with a depth sensor — any Apple Watch Ultra, or Apple Watch Series 10 or later — running watchOS 26 or later. |
| iPhone | iOS 18 or later, paired with the watch. |
Recording starts by itself when you go under, and the app turns on Water Lock: the touch screen stops responding so the water can't trigger taps. The screen shows your depth in large type and the dive time, which you can hide in Settings. There is nothing to press: the app detects the descent, the ascent and the surface on its own.
Apple gives apps two permissions to read the Apple Watch depth sensor. crazyDive has the shallow depth one, which gives readings down to about 6 m. Apple reserves the full-depth permission for certified dive computers. So beyond that point the number on screen stops moving: it is no longer your real depth, but "at least this much".
So it can't mislead you, as soon as the sensor reaches its limit the depth turns orange and gets a "+", for example 6.6+ m. The maximum depth in the summary when you surface is marked the same way.
Recording doesn't stop: the time keeps running and the whole dive is saved. With an Apple Watch Ultra, the watch itself stores the real depth in Health down to 40 m, and crazyDive later uses it on the iPhone to complete the profile (see Depth from Health). On an Apple Watch Series 10 or later, the watch's own sensor reaches about 6 m, so the profile stays at that limit.
crazyDive detects the surface and starts a countdown. You don't have to do anything:
Below 40% the watch warns you. Below 20%, if automatic battery saving is on, it stops recording motion to stretch the battery; depth and temperature keep recording.
Snorkel works just like a dive; statistics count it separately.
| Data | Where it comes from |
|---|---|
| Depth | The watch's depth sensor, one reading per second while you are submerged. Below about 6 m, the depth Apple Watch Ultra stores in Health. |
| Water temperature | The watch's sensor: minimum, average and maximum. |
| Position | The watch's GPS at the surface: entry and exit points. |
| Compass and motion | Optional: heading, gyroscope and accelerometer. They are recorded with the dive. |
| Weather | Apple's weather service, for the time and place of the dive: conditions and air temperature. |
| Time of day | Morning, afternoon or night, from the start time. |
Every dive is also saved as a workout in the Health app.
Search by text and use Filters: type (dive or snorkel), date (last month, last 3 months, this year), minimum depth and tags.
"Add dive" logs a dive made without the watch or from before you had the app.
The calendar marks the days you dived. Statistics show dives and snorkels, your deepest dive, total time, the coldest and warmest water, average depth and duration, activity over the last 12 months, your deepest and longest dives and the depth distribution.
"Last dive" and "Total dives" are available in Siri and the Shortcuts app.
Each dive's map marks the entry and exit, with a Surface or Sea floor layer. "Open in Maps" takes you there. Sites gathers every place you have dived on one map.
Everything is in Settings → Backup.
The app can offer a backup when you save a dive and remind you now and then.
It's automatic. The watch saves the dive and sends it when the iPhone is in range, and when you open crazyDive on the iPhone with the watch app open, the iPhone also asks it for anything still pending. If one doesn't arrive, open crazyDive on the watch and tap Settings → Apple Watch → Recover Watch Dives on the iPhone. "Clear Watch queue" deletes what the watch still has pending: use it only if those dives are already on the iPhone.
Below about 6 m, the depth is stored in Health by the watch itself, and that series reaches the iPhone on its own, a few minutes after the dive. While it's on its way, the dive shows “Downloading depth” and completes by itself: crazyDive retries when the dive arrives, when you open or return to the app, and when you open the dive. If it hasn't arrived after 24 hours, it switches to “Depth unavailable”: check the permission (Health → your profile → Apps → crazyDive → Underwater Depth) and tap Settings → Health → Download depth from Health, which tries right away and tells you the result. crazyDive keeps trying in the background for 30 days.
With iCloud turned on, your dives are kept in your own account and come back by themselves if you change iPhone.
| Section | What's there |
|---|---|
| Sensors | Record compass, gyroscope and accelerometer · Ask before each dive |
| Display | Show time while diving · Automatic battery saver |
| Auto-start & Auto-stop | Auto-stop · Stop sampling after N min · New dive after N min |
| Backup | Offer backup · Reminder · Create backup · Export · Import · Import backup JSON · Diagnostics · Contact Support |
| Health | Download depth from Health · Open Health |
| Apple Watch | Recover Watch Dives · Clear Watch queue |
No. It records and keeps your dives; it does not calculate decompression or warn you about limits. Always dive with your dive computer.
The watch's sensor, about 6 m; when it gets there, the depth turns orange with a "+". With an Apple Watch Ultra, anything deeper is filled in from the depth the watch stores in Health, down to 40 m. Why.
As a logbook, yes: you can add dives by hand and import them from UDDF. Recording needs a watch with a depth sensor.
Because of Water Lock, which prevents false taps. Turn the Digital Crown to release it.
Open crazyDive on the watch and then on the iPhone: when it opens, the iPhone asks the watch for anything pending. If it still doesn't arrive, use Settings → Apple Watch → Recover Watch Dives on the iPhone.
The first one is normal: the depth below 6 m comes from Health a few minutes later and completes by itself. The second one appears if it hasn't arrived after 24 hours; see Syncing.
Only in your own iCloud account, if you have it turned on. We have no servers.
Write to support@crazydev.app about anything: questions, problems, suggestions or feature requests. In the app, Settings → Contact Support opens your mail app with the address and subject filled in, plus your crazyDive version and iPhone model below. For a problem, use Settings → Diagnostics → Send to support instead: it attaches the app's log, which you can review before sending. With the Mail option in the list it's already addressed to support; with Gmail, Outlook or others, copy the address shown in the text into “To”.
Your dives are stored on your devices and, if you have it turned on, in your own iCloud account. No accounts, no servers of ours, no analytics, no ads. For the weather, the dive's location and time are sent to Apple's weather service; we never receive them.
The details are in the Privacy Policy.
Write to us about anything: questions, problems, suggestions or feature requests. We read and answer every email.