Captain Jack Aubrey and Captain James Dillon

There's no audience insert character who has never been on a boat. The closest to an audience insert is Dr. Steven Matron in the sense that he is not accustomed to sailing around on a man of war ship, a sloop. He doesn't know the difference between a frigate and a brig. And at one point he tries to ask a guy to explain what the things are without using naval terms. But that I would say is not really the focus of the novel or it is at least not the primary way that the novel works.