I'm away from my boat right now and wondered if the built-in rod holders on the gunnels are open at the bottom, or do they have a wire attached to keep the rod from going too deep?
Great! I was hoping that was the case. I wanted to try out one of those cup holders that is designed to fit in the rod holder. It has a slot cut into it for the "wire" to fit into. Hopefully the "post" you refer to will fit in the slot as well.