Who is Brown from Lord Hornblower and what is their importance?

Brown is Hornblower's loyal servant, and the ship's coxswain. Brown's native language is English, but he has learned to speak French with a passable accent. He is in his mid-twenties, powerfully built, and very intelligent. Brown has the peculiar mix of salty sailor, capable domestic, and masculinity which enables him to fully support Hornblower while remaining entirely in the background.