Ocean MAP User Manual
Apple Watch Ultra underwater navigation — from setup through entry, underwater operation and post-dive logging, in order.
▶ Watch it first (about 5 min) · Open on YouTube · 🧭 Try it in your browser
01Getting started
The first launch walks you through these once.
- Language — English · 한국어 · 日本語 · 中文 · Español · Deutsch · Français
- Data consent — storing logs and GPS coordinates on your device and your own iCloud (required); everything else is optional and can be changed any time.
- Tutorial — key features. Available again later under App · Info › How to use.
- Legal acknowledgement — confirming this is a supplemental tool.
Underwater, Water Lock disables the touch screen. Assign the Ultra's orange Action button to the
“Compass Action” shortcut and you can mark and confirm with a physical button while submerged.
Watch Settings → Action Button → Shortcut → “Compass Action”
Apple Watch Ultra (1 · 2 · 3) · watchOS 26 or later · iPhone (for logbook sync; not needed in the water)
02Home — five cards
The surface screen. Five full-screen cards stack vertically. Turn the Digital Crown or swipe up/down to move between them, and tap a card to open it.
| Card | What it does |
|---|---|
| Dive Now | Start the dive immediately with your current setup |
| Underwater Navigation | Origin, bearings and waypoints |
| Depth & Alerts | Water type · alerts · depth zero (no decompression features) |
| Logbook | Previous dives |
| App · Info | Language · profile · tutorial · diagnostics · terms |
Near the bottom the screen shows your surface interval (SI) and remaining NO FLY time when relevant.
03Navigation setup
Do this on the surface, before entry. Operating the watch underwater is hard, so set the course first.
Marking the origin (R)
At your entry point, tap Mark origin to store those GPS coordinates as the reference. All distances and directions are measured from this point, and the return guides you back to it.
Low accuracy is rejected. Give it 10–20 seconds with a clear view of the sky before tapping.
Bearing setup wizard
- Aim — point your wrist along the heading and hold until the dial locks green (within ±4° for one second). A haptic confirms it.
- Confirm — that bearing is stored as leg 1.
- Distance — set how far to travel on that heading with the Crown.
- Add leg 2 and 3 the same way if needed.
Leg 2's bearing and distance are measured from the end of leg 1, not from the origin. Keep that in mind when planning a course.
Undo removes the last leg; Reset clears them all.
04Depth & alerts menu
| Item | Description |
|---|---|
| Depth & Deco Notice | No decompression features — tap for the reason (section 12) |
| Water type | Salt / fresh. Used in the depth calculation. |
| Alerts · haptics | Warning haptics and sound on/off |
| Depth zero | Re-zero at the surface. Recommended when barometric pressure has shifted. |
05Diver profile
Set under App · Info › Diver profile. These are the starting values for distance estimation.
| Setting | Effect |
|---|---|
| Height | Anchor for distance per kick. Default 170 cm. |
| Fin type | Standard · long · split — different propulsion |
| Dive style | Relaxed · balanced · assertive |
After each dive the app compares the real GPS displacement between entry and exit with its own estimate and calibrates your personal stride. Expect some error on the first few dives.
06Entry — START DIVE
Tap the Dive Now card. The dive runs exactly as you set it up on the surface, and the settings menus are hidden.
- If no origin is set yet, it is marked automatically where you are.
- If waypoints are set, navigation starts immediately.
- Once you are actually in the water (below 1.5 m), distance and track recording begin.
Before entry you can cancel with ‹ at the top left. After entry it locks.
When a safety-affecting defect has been identified, a full-screen notice appears before the dive can start. Read it and tap I understand to continue. Update on your iPhone before entering if you can.
07The three underwater screens
Underwater you get three screens only — no settings. Turn the Crown or swipe up/down to move between them.
1 · Dive screen
| Readout | Meaning |
|---|---|
| Current depth | Real value to 6 m; below that, 6+ |
| Dive time | Elapsed since entry |
| Ascent rate | Green → amber → red. Slow down immediately on red. |
| Temperature | Measured water temperature |
| No deco calc | States that NDL and decompression stops are not provided |
2 · Compass (full dial)
The whole screen is the compass. The red lubber line is where you are pointing; the amber marker is where you should go. Overlap them and you are on course.
The corners show depth, distance to target and bearing, with the current state (e.g. Navigating) below centre.
3 · Digital map
Heading-up. Your origin R, numbered waypoints and the track you have travelled are drawn together.
Water Lock blocks it. Spin the Crown quickly to switch to return mode, and use the Action button if you configured it.
08Returning
To head back, spin the Crown quickly to switch to return mode. The target becomes the origin R, and the amber marker points toward it.
- Overlap the lubber line with the amber marker.
- Swim that way and the remaining distance counts down.
- Arrival is confirmed with a haptic.
It is estimated from sensors where GPS cannot reach. Strong current or irregular movement increases the error. Trust the direction first and treat the distance as a reference.
09How alerts behave
Alerts do not cover the screen for long — a covered screen means you cannot see your depth.
| Alert | Presentation |
|---|---|
| Ascending too fast | Top banner; the ascent-rate tile turns red. |
| Off the planned course | Top banner, when you deviate roughly 35° from the plan. |
| Other hazard alerts | Full screen, blinking four times then clearing. If the condition persists it repeats every 20 seconds. |
| SOS | Triggered by a long press. It stays up, because its purpose is to show your buddy. |
10After surfacing
- Dive summary — time, distance, kick count and max depth.
- Surface interval (SI) — time since your last dive, shown near the bottom of the home screen.
- NO FLY — remaining time counts down automatically.
- Site name — the iPhone app asks for it next time you open it (section 11).
DAN minimums are 12 hours after a single no-decompression dive and 18 hours after repetitive or multi-day diving. The app takes whichever is longer — that minimum or its own tissue-loading calculation. This is a reference; follow certified equipment and your training.
11iPhone logbook
Dives recorded on the Watch sync over iCloud. Four tabs: Log · Stats · Sites · Settings.
Naming the site
If a recent dive has no name, a card appears at the top of the list. Tap it and write the name.
- Nearby registered sites are offered first — pick one and it is reused.
- Leave Add to the map on and a new site joins the shared chart. Turn it off and it stays in your logbook only.
Entering max depth
Because the app measures only to 6 m, the dive detail lets you type the reading from your primary dive computer. This is how paper logs have always worked. The value you enter is what the logbook and statistics use.
Site map
Entry points are saved automatically; points of interest can be added by hand.
12The 6 m depth limit
Apple limits third-party apps to 6 m of depth measurement. Going deeper requires a separate entitlement.
| Depth | Shown as |
|---|---|
| 0 – 6 m | Actual depth (0.1 m steps) |
| Below 6 m | 6+ |
Computing and displaying no-decompression limits or decompression stops while depth can only be read to 6 m is dangerous. You could be at 25 m while the app reports figures based on 6 m. So we left them out.
If decompression features are ever added, existing owners pay nothing extra.
Bearing, distance and track are computed independently of depth, so they work normally below 6 m.
13Legal notice · disclaimer
What this is — a supplemental tool
Ocean MAP is a supplemental (backup) tool. It is not certified to EN 13319 or any dive computer standard and is not a replacement for a certified dive computer or gauge. It does not provide no-decompression limits (NDL) or decompression stops.
Your responsibility
- Dive planning, decompression and ascent decisions rest on certified equipment and your own training and certification.
- Always dive with a buddy and stay within the limits you are trained for.
- Depth, distance and bearing are sensor estimates and carry error. Current, body position, magnetic interference or device condition can make them significantly wrong, and following them may not bring you to your target or entry point.
- If you get lost or separated from your buddy or guide, follow your trained procedures (search, then ascend safely) first. The app does not replace them.
- Device, battery or sensor problems can freeze or turn off the display. Carry a backup such as a compass.
Disclaimer
You are responsible for decisions made using the information shown. To the maximum extent permitted by law, the developer is not liable for accidents, injuries or losses arising from use of the app. See the Terms of Use for the full text.
Privacy · data
- Dive logs and GPS coordinates are stored on your device and your own iCloud.
- Contributing to the shared chart (OceanMap Earth) and sending usage statistics are optional and off by default; chart contributions are only sent when you tap after surfacing.
- Contributions are anonymous and carry no personal identifiers.
- See the privacy policy for details.