Paul M. Elliot posted, on SSCA Forum, a link to his freeware tool NavMonPC, which reads a NMEA
data stream (instruments, GPS
, radar) in real time and displays that data in both gauges and graphs. It will also play back logged NMEA
data for reviewing "what happened when and where". It does not support charts
of any sort! This is not a replacement for SeaClear, etc. But there are some possibilities for those with good PC skills.
All of that said, this is an application that will leave some people saying, "I've died and gone to heaven!" At least that's what I said when I first used it.