Thoosa
Your boat's charts, instruments, logbook and objects library — clear, live and offline, on every Apple device.
Yet another navigation app? What for?
A tale of mishandled GPX files, forgotten instruments.
Not on the App Store yet
Thoosa isn't available on the App Store just yet — but you can already try it. Join the public beta through TestFlight, sail with the latest builds, and help shape the app. Your comments and feedback are very welcome.
A navigation station in your pocket
Thoosa turns your iPhone, iPad or Mac into a proper marine navigation station. The app reads your boat's data live — whether your network speaks NMEA 2000, NMEA 0183, Signal K or the Victron VRM cloud — and presents it as clear instruments, grouped automatically: GPS position, speed (SOG), heading (COG), depth, wind (TWS/TWA), engines, batteries, tanks…
On the chart side, Thoosa shows OpenSeaMap nautical charts (lights, beacons, traffic separation schemes) and imports your tracks, routes and waypoints as GPX, KML or KMZ. Plot a coastal route that automatically avoids land, keep an electronic logbook you can export to PDF, and let everything sync across your devices via iCloud — all of it works offline too. Free and ad-free, it's built for sail and power alike, coastal or offshore.
Universal connections
Automatically detects NMEA 0183/2000 or Signal K frames.
Connect using TCP, UDP broadcast & multicast to many servers with multiplexing. Or web to access Victron VRM cloud, and Signal K (snapshot and live supported). Even your device itself.
Replay any log file – NMEA, YD RAW, SeaSmart, Canboat, iKonvert & Signal K logs.
Live instruments
Automatically shows every reading on the network, grouped by theme — nothing to set up.
Position, speed, heading, depth and wind and almost everything (barometer, temperatures, windlasses, engines, batteries, tanks…) — from your boat's network.
Smart history graphs – SOG, COG, AWS, AWA, TWS, TWD, depth, barometer.
AI instrument analysis
From iOS 26 and macOS 26, on-device intelligence reads your live instruments and surfaces trends, outliers and things worth a look.
It all runs on the device — nothing is sent to the cloud.
Logbook
Records a tidy log of your voyages under way ready to print or export as a PDF.
Logs DSC and AIS alerts. Logs weather bulletins received over AIS or manually downloaded GMDSS METAREA forecasts.
Add any important things and free comments with pictures.
Charts & library
Free map with nautical information — lights, beacons, TSC from OpenSeaMap project.
Import GPX and KML/KMZ, browse your chart objects, and find them instantly from Spotlight.
Coastal routing
Plan a route right on the chart: tap a start and a destination, and Thoosa works out a great-circle path that stays clear of land and small islands — entirely offline.
Save the route to your library in one tap.
Built for Apple & iCloud
Everything stays in step across your devices.
With Home Screen and Lock Screen widgets, Live Activities and Siri shortcuts.
DSC and AIS alerts signalled by Notifications.
Beyond the Apple ecosystem too
The same app — nautical chart, instruments, AIS and the NMEA 2000 network,
powered by the same core — is coming to Windows, Android and Linux. On Windows
and Linux, unpack the archive and run Thoosa — no installation; on
Android, install the APK (allow unknown sources for the install).
Prototype builds: these are plain technical demonstrators — they reflect neither the final look and feel nor the final feature set of the app.
Frequently asked questions
Which devices does Thoosa run on?
iPhone, iPad and Mac (iOS, iPadOS and macOS), plus Apple Watch, Apple TV and Apple Vision Pro versions. Your data syncs across all your devices via iCloud.
Does Thoosa read NMEA 2000 and NMEA 0183?
Yes, both, live and auto-detected. It also replays log files: NMEA, YD RAW, SeaSmart, Canboat, iKonvert and Signal K.
Is it compatible with Signal K and Victron VRM?
Yes. Connect over TCP, UDP broadcast and multicast to several servers (with multiplexing), or over the web for the Victron VRM cloud and Signal K in real time.
Can I import GPX, KML or KMZ files?
Yes: import your tracks, routes and waypoints as GPX, KML and KMZ, then find them instantly from Spotlight search.
Does Thoosa work offline?
Yes. OpenSeaMap charts, the objects library and coastal routing all work with no connection — ideal once you're offshore.
Is there a logbook?
Yes: an electronic logbook kept automatically under way, exportable to PDF, logging DSC and AIS alerts, events and photo comments.
How much does Thoosa cost?
It's free. For now it's in public beta on TestFlight, ahead of its App Store release.