Found some links to free GRIB files that you can use with the demo version of the SeaPro Navigation software:
Free GRIB FilesLinks to various sites that offer GRIB files free to download.
|Global Marine Networks Free GRIB Files||World Wide||Wind data only|
|GRIB.US Free GRIB Files||World Wide||Desktop app required to download|
|Norwegian Meteo Institute direct link to GRIB Files||World Wide||Very detailed for some areas|
|Navcenter free GRIB Files||World Wide||Limited data|
|Tidetech free GRIB Files||World Wide|