Everything you need to know about Depthline, the sonar hardware, and how cave mapping works.
Depthline achieves 98.6% geometric accuracy on passage dimensions under typical cave diving conditions. Accuracy depends on water clarity, sonar unit positioning, and swim speed. Multiple passes of the same cave improve accuracy further.
The Depthline sonar module is our purpose-built unit for cave mapping. It's compact, mounts to standard BCD D-rings, and is rated to 100m depth. We also support select third-party sonar units — check our compatibility list in the app.
Yes — that's exactly where sonar shines. Unlike cameras, sonar doesn't depend on light or water clarity. Depthline produces accurate maps even in zero-visibility conditions where a diver can't see their hand in front of their face.
Depthline is a mapping tool, not a training substitute. We strongly recommend holding at least a cavern or intro-to-cave certification before entering overhead environments. Depthline enhances planning — it doesn't replace proper training.
Absolutely. Depthline maps any underwater environment — wrecks, reef walls, underwater structures, lake beds. The cave-specific features (restriction alerts, route planning) are most valuable in overhead environments, but the 3D mapping works everywhere.
Most single-dive cave maps process in under 5 minutes. Complex multi-passage systems or very long dives can take up to 15 minutes. Priority processing is available on Divemaster and Expedition plans.
Completely. Every map you create is private by default. You choose whether to share it with dive partners, publish it to the Community Cave Atlas, or keep it entirely to yourself.
The sonar module records all data locally during your dive — no connection needed underwater. You'll need a connection to sync and process your data afterward, but you can pre-download cave maps for offline reference before a dive.
Depthline syncs with Shearwater, Garmin, Suunto, and Ratio dive computers via Bluetooth. We're continuously adding support for more brands. The app can also function standalone with the Depthline sonar module only.
We're currently in a closed beta with a growing group of testers. Public launch is planned for late 2025. Join the early access program to get in before launch and lock in founding member pricing.
We're happy to talk caves, sonar, or anything diving.