Over the years I have patched a few cracked ribs and a small puncture hole in the hull of my Souris River using US composites epoxy and fiberglass cloth tape.  I am thinking the tape would work well to repair your cracks.  (You need to Login or Register to view media files and links) (bottom of page in various widths.)
The procedure I follow is to sand the area so the epoxy can make a good bond and then apply the fiberglass patch wetted out with epoxy. There will be some rough areas after the epoxy sets up on the edges due to loose fiberglass threads.  The next day, I then carefully grind this area flat and feather it relatively smooth before applying another layer of epoxy to finish the repair.  It takes a couple days to finish, but I have had good results with this method.