FAQ

The product

What is Submarius?

A mobile-first ocean-conditions app for spearos, divers, anglers, and boaters. It aggregates marine forecasts, satellite ocean colour, river discharge, tides, and harmful-algal-bloom bulletins into a single GO / NO / CAUTION verdict per dive day, with every input visible. See overview.

Where can I get it?

App Store for iOS, or in any modern browser at submarius.com (installable as a PWA).

Is it free?

The free tier includes today and tomorrow’s forecast, current water-clarity estimate, current verdict, tides, all safety features (SOS, buddy-GPS, shark alerts), spot library with E2EE backup, catch logging, and the offline base map. Pro adds the 7-day forecast, all the overlay layers, multi-spot trip planning, push notifications, and higher upload quotas. Pricing is on features/pro-vs-free.md.

What regions does it cover?

Globally. The model uses ocean and weather inputs that have global coverage (Open-Meteo, GEBCO, OpenStreetMap coastlines, satellite ocean colour). Some signals are US-only (USGS river discharge, NOAA HAB Forecast, NOAA Tides & Currents native). Outside those, the relevant components are absent and the model runs without them — the uncertainty band widens accordingly.

Water clarity

How does the visibility forecast actually work?

Three layers: a physical model anchored to satellite ocean colour (Lee 2015 Kd → Secchi with adaptive Case-1/Case-2 coefficient), with weather-driven penalties (rain, wind, tide, river plumes, HAB); crowd-sourced viz reports that pin recent estimates and calibrate the model over time; and a statistical refinement layer in regions with enough report density. Full detail at methodology/water-clarity-model.md.

How accurate is it?

The underlying Lee 2015 model achieves R² = 0.96 against 338 in-situ measurements globally. Submarius’s specific implementation adds weather-driven penalties and adjustments — some of which improve accuracy, some of which trade absolute accuracy for honest uncertainty quantification.

The honest answer is: it depends on the location and the recency of the data. Where satellite is fresh and reports are nearby, the estimate is tight. Where inputs are stale or reports absent, the uncertainty band is wide and the app says so.

Why does the band sometimes get really wide?

Because the model is being honest about uncertainty. When satellite coverage is stale (multi-day cloud cover, sensor outage), the oceanographic anchor is weaker and the band reflects that. When weather inputs disagree with each other, the band reflects that too. Tight bands when sources agree, wide bands when they don’t.

Why doesn’t it work for [my favourite dive site]?

If a site is hyperlocal — a specific cove, a specific reef on the back side of a specific island — the satellite resolution (2–4 km) can’t distinguish it from the surrounding water. Reports help bridge that gap. The more reports a region accumulates, the better the model performs there.

If the site is genuinely uncovered (inland, freshwater, beyond the forecast horizon), the app says so rather than guess.

What about Case-2 / coastal turbid water?

Submarius computes a Case-1/Case-2 blend factor from coastline geometry, distance-to-coast, satellite chlorophyll, and active HAB flags. Most products use Case-1 everywhere and overestimate coastal turbidity by 30–50%. We don’t. See methodology/kd490-explained.md.

Bite score

Is the bite score “AI”?

No. It’s a transparent composition of biological and environmental signals (solunar, barometric trend, fronts, tide, water temperature versus species preference, species presence, time of day, wind). Each contribution is visible. See methodology/bite-score-signals.md.

Why is the bite score per-species?

Because species differ. Redfish work the falling tide on flats, tarpon feed the incoming through inlets, snapper bite a different moon than mahi. A score that treats all fish the same is wrong half the time.

Safety features

SOS, buddy-GPS, and shark alerts are free? Forever?

Yes. The entitlement middleware in our backend explicitly bypasses subscription checks for safety endpoints. Permanent product policy. See features/safety.md.

What about Garmin inReach?

Hand-off to inReach satellite SOS for off-grid scenarios is planned but not shipped. Requires a Garmin partner integration.

Privacy

Are my dive spots private?

By default, yes — completely private to your device. When you choose to share, you pick the privacy level (buddy-only, public-fuzzed at ~5 km cell resolution, or public-exact for the rare “share my spot with the world” case).

Can Submarius see my exact dive spots?

If they’re private or buddy-shared: no, they’re on your device only (or sent encrypted to your buddy). If they’re public-fuzzed: no, only the H3 cell is sent — never the precise coordinates. The fuzzing happens on-device before the data leaves. Even with a court order, Submarius can’t recover the precise points of fuzzed spots. See features/privacy.md.

Does the app track me in the background?

No, except during an active buddy-GPS session (when you’ve explicitly paired with a buddy). Outside of that, location is “While Using” only.

Do you sell my data?

No. We don’t sell data, share with advertisers, or run ad SDKs. The business model is the Pro subscription.

Technical

Do you have a public API?

Yes — api.submarius.com. The API is documented and available for non-commercial use. Commercial integrations (B2B partners, research collaborations, white-label) are case-by-case. Get in touch via the contact link on submarius.com.

Is Submarius open source?

The documentation, methodology, FAQ, and brand assets in this repository are open-licensed (CC BY 4.0). The application source code is not open source.

Why is the source closed?

Two reasons. First, the model is the work that funds the company — publishing the calibration tuning would let competitors clone the product without doing the underlying calibration work. Second, the infrastructure (data ingest pipelines, caching, ACOLITE processing, etc.) is operationally non-trivial and we’d rather not maintain it as a public-facing project on top of running it for users.

The methodology is open. The art is in the calibration.

Can I run my own instance?

No, sorry. Submarius runs as a hosted service.

Why is there no Android app yet?

Capability rather than priority. The web app at submarius.com works on Android and is installable as a PWA, which covers the main use cases. A native Android build is plausible future work, not committed.

Business

Is Submarius a venture-backed startup?

Submarius is independent. We’re not seeking outside investment at this time.

How do I contact you?

Use the contact link on submarius.com. Security disclosures via SECURITY.md. General discussion at Discussions. Bugs via the bug template.

Are you hiring?

When we are, it’ll be on the website. Not currently.