qtVlm is a navigation software designed for sailing boats. It is also a free weather grib viewer that accepts all kinds of gribs. It can read and display maps in various formats, such as Vector charts (S57) Raster charts (kaps, geotiff, etc) and mbtiles charts.
qtVlm is certified Iridium GO! and can also access directly to your Great Circle (squid) grib subscriptions.
It includes an AIS module and an Instruments Module, that can retrieve data from various NMEA sources, or from internal GPS. It can also send performance data (VMG, target speed, etc) to a navigation system.
qtVlm calculates the best course using Routes and Weather Routings modules. Many options are available, like multi-routing to find the best departure date-time according to various parameters, routing on a pathway, or taking into account segments with engine. qtVlm can acquire position and NMEA information through various sources (internal GPS, tcp, udp or gpsd), and can display many navigation instruments and performance data.
Several grib files can be loaded at the same time, in order to be able to route using various parameters (winds, currents and waves for instance), or to compare grib models. Weather faxes images can also be loaded on top of gribs.
Charts can be loaded after transferring them on your device, qtVlm can also display maps from various Tiles Servers.
A Start Line Mode exists, which manages a regatta start line with chronometer, distances and times calculations, and displays a safe zone.
qtVlm can also be used In Simulation Mode. In this mode qtVlm will use wind and currents data from grib to simulate navigation. All instruments will be usable, and real live AIS targets are received from Internet. Beware not to collide with a real fishing boat or another qtVlm boat.
There is also a pure Virtual Racing Mode, using Virtual-Loup-de-Mer servers.
QtVlm is free for Windows, MacOS and Linux. There is also a free basic version for Android and iOS, which can be unlocked to full version through in-app purchase: Download Section
You can also found some usefull polars here
Contributions are welcomed to continue improving and maintaining the product: