I've done some research on stringer replacement and I am leaning towards fabricating marine ply stringers. I have questions on a few things. I was wondering if those of you that used ply formed the engine stringer from ply, or did you use doug fir? If you used multiple layers, did you bolt thru and if so did you leave the bolt in place after the epoxy cured? How did you then attach the engine stringer to the main stringers? Pictures if anyone has them would be helpful. Also, if anyone remembers previous post that addressed this, please let me know.