Tide-aware routing, an anchor alarm that doesn't sleep, and a chart that rotates with your compass. Built for the bight you love, the passage you keep making, and the slip you return to.
Open the chart ← other watersDrop a radius, stow the rode, and sleep. ChartNav watches your GPS trace against the drift circle and wakes you the moment it steps outside.
Running on an open phone browser tab or an installed PWA. No app-store friction, no subscription. The alarm works with your screen off and the device charging — the way an anchor watch should.
Drop waypoints, pull tides and currents into the same view, export GPX to your chartplotter. The plan you made on Thursday is the plan you execute on Saturday.
Route legs compute distance and bearing in real marine units. Tide-stage checkpoints tell you whether that shoal will be a hazard or a shortcut when you arrive. Save routes to your device — they're yours, offline.
NOAA CO-OPS tide and current predictions, NDBC buoy wind and wave, live on the same chart. The nearest station auto-locks to your position — you don't have to go looking.
Current arrows show set and drift at slack, flood, and ebb. Buoy badges report wind, gust, wave height, and air pressure. If the harbor you're entering has a station, you see it. No tab-switching, no alt-app.
One-tap mark-and-record when someone goes over, with GPS position and drift vector.
NEXRAD Level 2 + NIDS, lightning, alerts, fog zones. Live on the chart.
Chart heads up with your heading. The course-over-ground vector stays locked ahead.
Know what's nearby — ferry schedules, fishing fleets, commercial traffic. Live VHF broadcasts.
Routes and tracks export to your chartplotter, OpenCPN, or a handheld — standard GPX 1.1.
Point your phone at the horizon — vessel names and ranges appear as overlay annotations.
A heads-down nav banner with SOG, COG, HDG, and cross-track — large, legible at a helm.
Installed PWA caches the chart, fonts, and your routes. Sail out of cell range, still see charts.
What cruisers want to know before they bookmark the chart.
Yes. ChartNav combines a full NOAA ENC chart plotter, live AIS, NEXRAD weather, NOAA CO-OPS tides and currents, NDBC buoys, route planning with GPX export, and an anchor alarm — free, no subscription, no account. Navionics and Aqua Map both require paid subscriptions; ChartNav doesn't.
Yes. Set a drift radius, keep the tab open or use the installed Progressive Web App, and ChartNav watches your GPS. The alarm sounds the moment your boat exceeds the radius.
Yes. Routes export as GPX 1.1 — compatible with Garmin, Raymarine, Simrad, B&G, Lowrance, Humminbird, OpenCPN, and handheld GPS units.
Installed as a Progressive Web App, ChartNav caches charts, routes, and preferences on your device. It keeps working when cell coverage drops. Expanded offline chart caching is in active development.
NOAA CO-OPS tide predictions render as bar gauges on the chart at every station. Tap any station for a 24-hour curve with HW, LW, and slack. Current stations show as arrows with set and drift.
No. ChartNav is an aid only. Always consult official NOAA nautical charts, notices to mariners, and certified equipment alongside it.
No signup. No install required. Same chart that's already on the water with thousands of boats.
Open ChartNav