How to section stringers?? fiberglass boat

[Ned L]

Giving it more thought,... in a pleasure boat application, and considering they are glassed in you should be fine going down to an 8:1 ratio, or even a tad lower. --- You could most likely get away with even less, but I wouldn't really be considering that good workmanship.

 

[DeepBlue2010]

I agree with JbCurt, the pictures you posted makes me think maybe you did not cut enough but I can?t be sure without more pictures and close-ups.
The practical concerns you mentioned in your post #12 about implementing the tapered type of joint is what makes it ? IMHO ? not practical in your case. If you were fabricating the stringer as a whole outside the boat, this would have been different story. But splicing into an existing and installed stringer makes this type of join really hard to implement no matter how good it sounds in theory.

IMHO, if you use a simple sister joint, it will be more than enough for what you trying to do. Something like this? glue the heck out of it and clamp it then glass over it with 1708. Couple of layers will make it plenty strong