I 'm working on stripping down my 1979 CCP 20 for a rebuild. Today when I removed the rubrail, I discovered a row of 4 holes aprox 3/4" diameter on the hull deck seam. They pass through both the hull and liner at the seam, and and I'm sure that any water that seeps past the rubric finds its way into the boat.
Anyway, what is the purpose of the holes? Did they allow seam to line up better? Were they attachment points for a hoist when the hull and liner were mated? Was SOP to leave the holes unfilled?