Update...not so bright...

[Stillrunning]

Someone on this site knew of a product that you can pour into the stringer that would do the trick. From what i read you could just shave off the top of the stringers exposing the insides. Clean out all the rotted wood and then fiberglass the seperated areas. Then fix any holes and places that the stuff would run out of. Then just mix it up and pour it in and that would be an easy rapair.