The grib file i created using Zygrib and NOAA-GFS (standard data) of the WHOLE world, with wind arrows showing the strength and direction of Wind.
It consists of 12 sets of 6 hr predictions of wind for the next 3 days.
The spacing on the wind arrows is 120Nautical Mile apart.
A user using OpenCPN(Open-source Navigation Package. Zygrib (GPL3 Open Source) or even in future Open Street Map or Open SeaMap could automatically super-impose the Grib Weather Data onto a Chart and create their own Weather Pictures.
This dat would be immensely beneficial to all Mariners.
But a user could not reverse a weather picture and create 3 days of gribs.
My vote is definitely go with the Grib weather file.
The Data is freely available every six hours.
Boaters rich or poor, Europe or Africa all over the world want accurate weather.
Accurate Weather will help save lives at sea .
The "Grib2" format allows for Data sets to be broken up and recombined.
Outernet could transmit small geographical data sets which could be easily combined.
Many free open source projects already exist to manipulate the data.
The data may already be available as smaller subsets and Outernet may only have to mirror a government Weather Bureau data share every six hours.
Someone like SOLAS "Safety Of Life AT SEA" or the UN might pay for this as a Community Service Obligation to Mariners.