Weathernews has introduced an offline mode for its SeaNavigator for Master navigation application, allowing ship masters to access stored weather forecasts and voyage plans when onboard internet connectivity is unavailable.
The new functionality follows onboard trials conducted between February and April 2026, during which masters reported connectivity problems affecting access to live weather information. Issues included unreliable coverage in parts of the Southern Hemisphere, latency exceeding 1,000 milliseconds and restrictions on satellite services in some coastal waters.
Offline mode uses a companion application, Data Mirror Manager, to download selected weather information for specific sea areas and forecast periods ranging from seven to approximately 14 days.
Available data layers include wave height, swell, storm information, weather charts, typhoon tracks, wind and currents. Downloads can be scheduled up to four times daily to incorporate updated forecasts, while an estimate of the required download size allows crews to manage available bandwidth.
When connectivity is interrupted, SeaNavigator automatically switches to stored data, allowing masters to continue reviewing their Active Passage Plan and alternative routes alongside the downloaded forecasts. The application displays the time of the latest data update, while live information is restored automatically when connectivity returns.
Route simulation and the application’s AI Agent remain dependent on an internet connection and are not available in offline mode.
“Our onboard trials have repeatedly highlighted the importance of connectivity, fast loading times and the need for offline capability when internet access cannot be guaranteed. It was one of the clearest messages we heard from masters,” said Craig West, CEO Europe at Weathernews.
SeaNavigator for Master was launched in December 2025 to support ship masters with route assessment, weather risk analysis and voyage planning. Offline mode is available through a new desktop application, which can be installed using a shore connection or USB drive where onboard downloads are impractical.
