The spearfishing app built around the one question that actually matters.
Every marine-weather app tells you the wind and the swell. That's table stakes. But spearfishing comes down to one thing: can I see the fish? Submarius answers that directly — with real water-clarity forecasts, tide and moon windows tuned for hunting, and a color-coded verdict you can read in one second.
Water clarity is the whole game.
In the Caribbean you're shooting at 25 meters of visibility and every fish is obvious. In the Chesapeake you're lucky to see your own gun tip. Most apps ignore this entirely. A few show "wave height" and call it a proxy. That isn't how turbid water works.
Submarius uses satellite-derived Kd490 turbidity from NOAA CoastWatch, feeds in recent river-discharge plumes from USGS, applies a physically-motivated wave-mixing model, and blends in community post-dive reports. The result is an honest Secchi-depth estimate — with explicit uncertainty bounds — for every dive window.
When the forecast is wrong, the dialog tells you why: whether it's proxy data in a region we don't yet have direct measurements for, a recent storm that hasn't cleared, or a river that's dumping sediment. No black-box "you're good, go!" — actual reasoning.
Tide + moon = hunting windows.
Slack tide for easy entries and clear water column. Spring tides for moving bait, neap tides for clarity. First and last quarter moons for predictable currents. Submarius computes every high and low, every phase, every window — and surfaces the 2–3 hour stretch each day with the highest verdict score.
This is the "best window" chip on the home dashboard. Plan your 5am alarm around the data, not around the weekend.
Your spots stay your spots.
Spearos guard GPS coordinates like combinations to a safe. Submarius was built with privacy as a day-one requirement, not a bolt-on:
- Public spots you share are fuzzed to ~1 km — nobody can reverse-engineer your honey hole.
- Personal dive logs with precise coordinates never leave your device.
- Community viz reports submit only a coarsened (~1 km H3-tile) location alongside the report.
- Per-spot ACLs: private, friends-only, or public.
Privacy enforced structurally, not by policy.
Safety that stays free, forever.
OCEARCH tagged-shark alerts, community shark sightings, buddy GPS sharing, SOS, and (phase 2) breath-hold blackout monitoring are permanently free. No Pro gate. No paywall. Some features shouldn't cost money — and gating them would be a PR disaster anyway.
What a verdict looks like.
Open the app and you get a number between 0 and 10, a word (PRIME, GOOD, FAIR, CHOPPY, ROUGH), and the one sentence that explains the driver: "Visibility estimate poor — turbid water likely, rising tide, 12 kts NE, 1.8m SE swell." Tap any factor for the full breakdown.
Every factor is tappable — wind, wave, swell, tide, moon, water temp, viz, best window — opening a drawer that explains what the number means, how heavily it's weighted for spearfishing, and a 24-hour forecast trend.
Ready to stop guessing?
Free forever for conditions, verdicts, and all safety features.