CHRTsail

CHRTsail is the product of real frustration with the boating chart-plotter landscape. Charts are either dumbed down, or old and pixelated — and, either way, hard to actually use. We said enough: it's time someone built modern charts and software for the mariner of today and tomorrow. That's what CHRT is all about.

CHRTsail is a chart plotter engineered like a precision instrument, built from the ground up on a modern stack. Official chart data, full control over how it renders, and a platform built to work just as well offline as online.

BETTER CHARTS
Every chart is vector data, rendered fresh on your device — not scanned paper, not a static image — so it's crisp at any zoom, on any screen. Choose your portrayal: the official IHO S-52 ECDIS symbology, or a softer house style built for easy reading in daylight. Choose your detail level too, from a clean overview down to full harbor complexity. CHRTland adds relief, contours, roads and place names on the land side, so the shore reads as a shape, not a blank space. Charts themselves are official Electronic Navigational Charts, sourced directly from the issuing hydrographic office — today, that's NOAA, covering U.S. waters including Alaska, Hawaii, Puerto Rico, the U.S. Virgin Islands, Guam, and American Samoa. More coverage is in development.

OFFLINE, BY DESIGN
CHRTsail is built offline-first, not offline-as-backup. Download full chart regions before you leave the dock and keep navigating with no signal at all — built for a multi-day passage, not just a harbor stroll. Hazard alerts keep working offline too, clearly labeled as reading only what's downloaded to your device — never silent, and never pretending to see everything the online check would. The barometric-pressure trend needs no network to begin with, and logs itself alongside your track either way. Running low on charge? Emergency Battery Mode stretches it by slowing how often things refresh — never by turning off anything that matters.

ONE ACCOUNT, EVERYWHERE
The same CHRTsail account carries across iPhone and iPad, CHRTsail for Mac, and CHRTweb in your browser (in beta) — plan a passage at the chart table, then pick it up on the water. Live position and hazard alerts live here, on the device that's actually with you underway.

NATIVE, TOP TO BOTTOM
Live Activity, Lock Screen, Dynamic Island, and Home Screen widgets — built in, not bolted on. Your position, speed, and next waypoint stay visible while you're underway without unlocking your phone; a Home Screen widget surfaces the tide without opening the app at all. Every setting — chart style, complexity, units, safety depth, night mode — follows you everywhere.

WAYPOINTS & ROUTES
Drop a waypoint with a tap, plan a multi-leg route across a whole passage, and navigate to any mark with bearing, distance, time to waypoint, and cross-track error. Share a route with your crew — sent directly to people you've connected with, never a public link.

WEATHER, TIDES & CURRENTS
NOAA harmonic tide and current predictions, computed right on your device — a scrubbable curve, station markers on the chart, and the next high or low wherever you're looking. Observed conditions from the buoys that are actually measuring nearby — wind, waves, pressure — with the station named and the reading's age always in view. Full National Weather Service marine zone forecasts and active warnings, read straight from the source, not trimmed to a headline.

AND EVERYTHING ELSE A PASSAGE NEEDS
Hazard alerts ranked against your own declared safety depth — arithmetic, not a guess, and never a verdict. A logbook that records itself, passage after passage. Anchor watch, Man Overboard, and a boat profile that knows your draft.

CHRTsail provides situational awareness only. It is not SOLAS-compliant, not a certified ECDIS, and not intended for primary navigation — and it is not a substitute for official charts, publications, or prudent seamanship.