For emergency communications on the open sea, an Inmarsat or Iridium phone is the right choice. As you have on the open water a clear view to the sky in all directions Iridium is suitable for all waters from the North Pole to the South Pole, Inmarsat is for the waters within the Arctic Circle also a good deal.
If you like to use your satellizte phone as modem in order to receive weather data (grib files), we recommend Iridium. Although in general Iridium and Inmarsat both have a dat rate up to 2.4 kbps, but in our opinion Iridium works in practice more reliable and easier.
The Iridium GO!, the Iridium Extreme and the IsatPhone 2 offer a programmable SOS button and the option for tracking with our tracking platform www.m-cramer-tracking.de