The bite, the weather,
the window.
A free fishing boat navigation app with NOAA tide tables, NEXRAD Level-2 radar, live current vectors, NDBC buoy observations, and AIS awareness of every commercial hull nearby. Built for the boat you run, the spots you fish, and the weather you actually have to call.
Read the water ← other watersFish the window, not the clock.
NOAA CO-OPS tide and current predictions, auto-located to your position. See slack, flood, and ebb for every station on your grounds — no jumping between apps.
Current arrows show set and drift at the spots you actually fish. Tide gauges mark stations on the chart. Tap any station for a full 24-hour curve. The best bite, and the best drift, make themselves obvious.
Read the sky before you call it.
NEXRAD Level-2 radar, live lightning, NWS alerts, GOES satellite, and NDBC wind and wave — overlaid on the chart you're already running. Cancel or go with something better than a screenshot from your weather app.
Small Craft Advisories paint as polygons over your grounds. Afternoon thunderstorms show as they develop. Wind and wave from the nearest buoy read out live. Clients get a real briefing, not a vibe.
See the boats around you. Track your own.
Live AIS on the chart means you know where commercial draggers are working, where the party boats fished yesterday, and where your sister boats are right now. MMSI watchlist keeps your whole charter fleet on one screen.
Charter operators use ChartNav to dispatch, spot under-producing grounds, and answer the "where are they?" phone calls without a satellite subscription. AIS is public VHF broadcast — ChartNav just renders it cleanly.
Everything you call on a shake-down day.
Tide curves
NOAA CO-OPS tide predictions with 24-hour curve per station. Slack, flood, ebb visible at a glance.
NEXRAD radar
Level-2 reflectivity, velocity, and echo-top products. See pop-up storms while they're forming.
Anchor alarm
Set a drift radius for overnight stays. ChartNav wakes you if the hook drags.
MOB marker
One-tap position capture when someone goes over. GPS lat/lon, time, drift vector on the chart.
AIS traffic
Every AIS-equipped hull nearby — commercial draggers, party boats, tankers. Public VHF broadcast.
GPX export
Save routes and waypoints, export to Garmin, Raymarine, Simrad, Lowrance, Humminbird, or OpenCPN.
Charter fleet
Unlimited MMSI watchlist. Track every boat you run from one screen, with AIS-dark alerts.
Installs as PWA
Add to Home Screen on iOS or Android. Works offline once tiles are cached. No App Store friction.
Questions from the wheelhouse.
Straight answers. If we don't cover it, write us.
Is ChartNav a free alternative to Navionics SonarChart or Fishidy?
Yes. ChartNav combines NOAA Electronic Navigational Charts, CO-OPS tides and currents, NEXRAD Level-2 radar, NDBC buoy observations, and live AIS — all free, with no subscription. Navionics and Fishidy both require paid chart subscriptions; ChartNav does not.
Does ChartNav show tide windows for my fishing spots?
Yes. NOAA tide stations render on the chart with bar gauges. Tap any station for a full 24-hour tide curve with slack, flood, and ebb clearly marked. The nearest station auto-locks to your GPS position.
Can I track my whole charter fleet on ChartNav?
Yes. Add each vessel's MMSI to the fleet watchlist for unlimited hulls on a single screen, with live speed, heading, status, and AIS-dark alerts when a boat stops broadcasting.
What weather data does ChartNav show for fishing days?
NEXRAD Level-2 and NIDS products, GOES satellite, live lightning strikes, NWS watches and warnings, dense-fog advisories, wind barbs, and NDBC buoy wind/wave — all overlaid on the same chart.
Can I export fishing routes to my chartplotter?
Yes. Routes and tracks export as GPX 1.1. Imports cleanly into Garmin, Raymarine, Simrad, Lowrance, Humminbird, and OpenCPN.
Does ChartNav work offshore without cell signal?
ChartNav installs as a Progressive Web App. Once loaded, charts and routes cache locally so the app continues to show your position and chart even with no connection. Expanded offline chart caching is in active development.
Call it before the sun's up.
Free to use. No account required. Tide, radar, AIS, fleet — open in a browser tab.
Open ChartNav