Thanks for your replies @Syed, @branko.
While you are in progress with that, I am going to do tests with tuners and dishes on board if I can. Let me know if you need details about grib files, on board communications or something.
Some extra info...
Grib are data files which can be read by viewer programs.
If you have satellite internet connection you will be able to either make requests from the program of an exact location and add all the data you are interested in (wind, rain, pressure, temperature, waves...) or download grib files (wind or waves) of predefined zones. Expensive.
If you have a HF transmitter and a pactor modem, you will be able to make requests of grib files by mail. That involves too much expensive devices and likely interferences. There are two services, one of then free but you need a Ham license.
Wind of all predefined zones is 3MB total weight. Waves are about the same. Files are from 5kb weight to 200kb . They are automatically generated 4 times at day but for general navigation it will be enough with just one update.
Having these files available to automatic unattended download from outernet it would be the best, cheapest and easiest option.