The 2nd photo of the stancion base and deck looks pretty ugly. Hard to tell if the deck is significantly deteriorated (but it looks bad).
The deck and hull joint is usually sealed with some sort of sealant when the boat is constructed, and the joint is held together with bolts or screws all along the deck. The aluminum toe rail is often incorporated into this seam…
here is the design for my O’Day 322 : in my case, the aluminum rub rail is bolted on, thru the hull/deck joint And the toe rail is just bolted down through the deck.
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Greg