Rotten stringer

[Fore and Aft]

Claudiopinto down under I would call it a beam shelf (not that you have any beams in a traditional sense). I am still keen on using timber, probably a hardwood. Maybe two 20mm laminations. Mainly because it provides a structural element to the repair. I zoomed in on the fiberglass cut out and it doesn't look thick enough to be structural. I also like the idea of fiberglassing the deck hull join before installing the stringer.
Cheers

[roland stockham]

This IS structural and the timber is an important in providing stiffness to the beam. So 2 things, yes you do need to open up the stringer and remove and replace the timber. I would suggest using a laminated beam which will be significantly stronger than solid wood. Any rot resistant wood will be fine or you could use strips of marine plywood. Second issue is that it almost certainly rotted due to a leak in the hull to deck joint so you also need to remove the cap rail and re-bond the joint.

[Claudiopinto]

Originally Posted by roland stockham

This IS structural and the timber is an important in providing stiffness to the beam. So 2 things, yes you do need to open up the stringer and remove and replace the timber. I would suggest using a laminated beam which will be significantly stronger than solid wood. Any rot resistant wood will be fine or you could use strips of marine plywood. Second issue is that it almost certainly rotted due to a leak in the hull to deck joint so you also need to remove the cap rail and re-bond the joint.

Thank you for your help.
I'm going to fiberglass the outside under the cap rail so there are no more leaks.
and from the inside remove the beam and replace it as you said, and fiberglass the interior deck to the hull joint and the beam.