Water-clarity forecasts, honest bite scores, and a single GO/NO verdict per dive day — for spearos, divers, anglers, and boaters.

This repository is the public documentation for Submarius — methodology, data sources, feature explainers, FAQ, and changelog. It does not contain source code or compiled apps. The product ships through the App Store and the web; this repo exists so the model behind it is open to scrutiny.

A mobile-first ocean-conditions app built around one question: should I go, or not?

Most marine-weather apps hand you ten numbers and let you decide. Submarius runs the integration step itself: tide stage, swell, wind history, satellite-derived water clarity, river plumes, harmful-algal-bloom bulletins, moon phase, and bathymetry — combined into a single GO / NO / CAUTION verdict per dive day, with every input tappable for its full reasoning.

Built for:

• Spearos and freedivers — water clarity is the question that decides the trip. Submarius is the only app that forecasts it from physically grounded oceanography (NOAA CoastWatch satellite Kd490 → Secchi via the Lee 2015 model), not vibes.
• Anglers — bite-score from solunar timing, barometric pressure, recent fronts, and tide stage, with the inputs visible.
• Divers and boaters — tides, currents, marine forecast, reef and wreck overlays, OCEARCH tagged-shark alerts, free SOS with Plus Code rescue location, buddy-GPS sharing.

• docs/overview.md — the product map: every feature, every data source, who it's for.
• docs/features/ — one page per feature (water clarity, bite score, the verdict, tides, shark alerts, safety, offline mode, privacy, Pro vs free).
• docs/methodology/ — how the models actually work. Cited oceanography, no hand-waving.
• docs/glossary.md — every acronym defined plainly (Kd490, Secchi, H3, Case-1/Case-2, CDOM, FNU…).
• docs/faq.md — real questions from real users.
• docs/press/ — press kit and coverage log.
• CHANGELOG.md — every shipped release, dated.

Mirrored at docs.submarius.com via GitHub Pages.

• No source code. The Go backend, React user app, admin SPA, and Astro marketing site are private.
• No APKs, no IPAs, no binaries. The app distributes through the App Store; the web app runs at submarius.com.
• No internal calibration coefficients, model weights, training data, infrastructure topology, or commercial details.
• No roadmap. Shipped is shipped; everything else is just intent.

If you're looking to build on Submarius data, the public conditions API is documented at submarius.com — get in touch via the contact link there.

Submarius fuses three satellite ocean-color sources (VIIRS-SNPP daily, the NOAA VIIRS+OLCI multi-mission DINEOF gap-filled product, and GOES-16 ABI processed hourly via ACOLITE) using inverse-variance weighting in log-Kd space — the maximum-likelihood combination for independent Gaussian observations. The fused Kd is converted to Secchi depth via the Lee 2015 mechanistic model (R² = 0.96 across 338 globally distributed in-situ measurements), with an adaptive coefficient that switches between Case-1 (open ocean, ~2.38) and Case-2 (coastal, sediment- and CDOM-dominated, ~1.5) based on coastline-geometry enclosure, distance to shore, satellite chlorophyll, and active HAB flags. The result is then penalized for recent precipitation (river-plume + nearshore runoff, ~2-day lag), wind-history resuspension over shallow bottoms (W²/H scaling, Green & Coco 2014), tide-stage current effects, and HAB bulletins. Bathymetry caps the estimate at bottom_depth × 1.5 when the seafloor is shallower than the 122 m diver-relevance horizon — a four-metre bottom can't yield twenty-five-metre visibility. Every component contributes a (value, weight, reason) triple, surfaced in the API response so the user can see exactly why the number is what it is.

Full methodology: docs/methodology/water-clarity-model.md.

Submarius pulls from public oceanographic and meteorological providers. None are proprietary; we just integrate them honestly.

• NOAA CoastWatch ERDDAP — satellite Kd490, chlorophyll-a (VIIRS, multi-mission DINEOF)
• NOAA NODD on AWS — GOES-16 ABI L1b for sub-daily ocean color (processed via ACOLITE)
• NOAA NDFD / HRRR — short-range surface wind, marine forecast
• Open-Meteo Marine + Forecast — wind, swell, wave, sea-surface temperature, precipitation history
• NOAA Tides & Currents — tide predictions, water level, currents
• NOAA HAB Forecast — Gulf Coast harmful-algal-bloom bulletins
• USGS Water Services — river discharge and turbidity (US)
• OCEARCH — tagged-shark tracking
• GEBCO — global bathymetry
• OpenStreetMap — coastlines, reef and wreck features
• Marine Regions — maritime boundaries, MPAs

Full provider list with links and license terms: docs/methodology/data-sources.md.

Submarius operates under three rules that show up in every part of the product:

1. Never claim what we don't measure. No "great viz today!" copy unless the satellite or recent reports actually support it. Where the model is uncertain, the app says so.
2. No hardcoded jurisdiction-specific data. No "good in Florida, bad in Maine" lookup tables. Classifications come from coastline geometry and oceanographic inputs, not place names.
3. Safety is permanently free. OCEARCH shark alerts, SOS with Plus Code rescue location, dive-buddy GPS sharing, and emergency contact are bypassed by the entitlement middleware regardless of subscription tier.

More: docs/methodology/data-honesty.md.

• iOS — Download on the App Store
• Web — submarius.com (works on any modern browser; install as a PWA)
• Pricing — Free tier with all safety features. Pro is $12.99/mo, $99/yr, or $149 lifetime.

• Press kit, screenshots, founder bio: docs/press/press-kit.md
• Coverage log: docs/press/coverage.md
• General inquiries: via the contact link on submarius.com
• Security disclosures: see SECURITY.md

The contents of this repository — prose, diagrams, and brand imagery explicitly placed in assets/brand/ — are licensed under Creative Commons Attribution 4.0 International. Quote, link, adapt, translate. Attribution back to Submarius is appreciated.

The Submarius name, logo, and product trade dress are not covered by the CC BY licence.