Stringer Replacement Harris - materials, process, options........

[HiZ]

Ok,

My friend has a Harris Float boat, deck style with a 5.7 and Alpha set up
We have removed the power and both stringers are gone. (like a sponge)
I have found the spot of water intrusion, drilled drain holes (non-sealed)
So, we are going to tear out and replace them. Bulkhead is ok, Transom ok.

What products should we use and what process.

I know quite a bit about glass and lamination.
But can we laminate on the inside only
Or do we need to secure from the outside also?

Just some of your expert thoughts on this........

Thank you