will open UNKNOWN charts.
See? (click the picture to see it better)
so try just bsbfix...and by the way, it seems to work fine (in XP anyways) to just drag the chart file onto bsbfix.exe...put a copy in your chart folder and try it...one at a time only this way.
You need be careful calling them MERCATOR alright because first off, it has more characters than UNKNOWN -8 vs 7 letters- and that will be an issue that I think bsbfix can fix , but you and WE are all better off without blithely copying mercator in if there's any chance you are going to share these charts.