The first honest water clarity forecast.
You can't spear what you can't see. You can't enjoy a dive when the water's a brown soup. And yet every other app ignores this signal or uses surface chop as a proxy — which doesn't work in bays, sounds, or estuaries. Submarius is the first app built around a real underwater-visibility forecast.
The three-layer architecture.
Our clarity forecast is built in three layers, designed to be credible from day one and to sharpen over time:
Satellite Kd490 → Secchi depth via Lee 2015 (R²=0.96), plus wind-wave mixing via a W²/H (wave energy over depth) formulation, plus river-discharge plume detection, plus harmful algal bloom bulletins from NOAA HAB tracking. All published oceanography — no invented heuristics.
After every dive, spearos and divers submit a single-tap visibility rating. Each report is paired with the full feature-vector snapshot (conditions at that time and tile) so our model learns what "actually happened" vs "what the model predicted."
Trained on the growing report dataset, a gradient-boosted quantile regression model outputs p10/p50/p90 bounds — so you get "probably 6–12m, most likely 8–9m" instead of a fake-precision "9.2m."
What the drawer actually shows you.
Tap the Visibility card in the app and you drop into an immersive underwater scene: a dogtooth tuna swimming at 20 feet, a diver silhouette at 40 feet, both attenuated by Beer-Lambert optics at the current viz level. The fish fades. The diver fades harder. You can see what the number means, not just read it.
Below the scene: the raw Secchi estimate, confidence percentage, reason, and a 24-hour forecast trend. No hype. No "WATER IS GREAT!" buttons.
Honesty over hype.
A cornerstone principle at Submarius is the data honesty rule: we never claim what we don't measure. If we're using a proxy — like swell height as a "surface state" hint — we label it as a proxy. If we don't have direct turbidity data for your region yet (many inland lakes, remote coastlines), we tell you that, not invent a number.
For every dive-mode verdict, the dialog includes an always-on caveat: "We don't yet have direct water-clarity data for this location — apply local knowledge." A user who's burned by a "GOOD" verdict on a blown-out day loses trust forever. Trust is the product.
"Best viz window this week."
Applying the same model to forecasted future feature vectors gives you the three-hour stretch in the next seven days with the highest predicted clarity. Unique to Submarius. Essential for anyone planning a weekend trip.
Private even from us.
Community viz reports contribute to the model — but your precise dive location never crosses the wire. Only an H3-tile-fuzzed (~1 km) coordinate is submitted with the report. Personal dive logs (with exact GPS) live in device storage only. If a Submarius employee queried the database tomorrow, they'd see who dove in what general area — not your spots.