Carver Santego 3067 (1990) - How strong are the gunwales?

[SantegoGuy]

I own a Carver Satnego 3067 (1990).

I'd like to mount either a track system or rod holders to the aft gunwales.

The underside to these gunwales don't seem to be accessible (unless I'm missing something?)

So my question is, how strong/thick are the aft gunwales. Do I have to use a brace of some sort underneath?

Does anyone have expericence with mounting anything heavy to the aft gunwales?

Thanks