Perhaps of related interest, Predict
Wind has a free program called Predict Wind
Offshore. You use it to generate a grib file request for the area you select from the base map in the program. You then send this request to Predict Wind by sat
phone or
HF radio and a short while later you download the grib file to view on your grib viewer. To use it with
HF radio you send an
email to Predict Wind with the grib file request as an attachment. When you next download emails you will get the grib file. I don't know if these grib files are any more accurate than others available. One would have to determine that for the area they were sailing in.