Marine Nav
Tides, currents and celestial navigation.
An offline navigation toolkit for sailors and navigators. Predict tide heights and tidal currents — including slack water — work a celestial sight from sextant altitude to a fix, read magnetic declination from the World Magnetic Model, and solve great-circle distance and bearing. Everything is computed on your device from published data, so it keeps working with no signal at sea.
What's inside
Tide heights and tidal currents, with slack water
Celestial sight reduction — sextant altitude to a fix
Magnetic declination from the World Magnetic Model
Great-circle distance & bearing · 100% offline
No account, no tracking, no data collection. Marine Nav works fully offline.
Questions
Does Marine Nav work offline?+
Yes. Marine Nav runs entirely on your device, so it works with no internet connection.
Is there an account or subscription?+
No. There's no sign-up, no login, and no subscription — just download Marine Nav from the App Store and open it.
What data does Marine Nav collect?+
None. It collects, stores, and transmits zero personal data — nothing ever leaves your device.
Which devices are supported?+
Marine Nav is available for iPhone, iPad & Mac.
More from AISixteen
Get Marine Nav
Tides, currents and celestial navigation. On-device, no account, no tracking.
Download on theApp Store