What is Aubrey's main concern in the novel, The Thirteen-gun Salute?

Aubrey's primary concern is his status within the Royal Navy. Due to trumped up charges for crimes he did not commit, Aubrey has been ejected from the Royal Navy, and thus, he begins the novel as a private citizen, though in command of a privateer. Over the course of the novel, he is reinstated to the Royal Navy with his previous rank and no loss of seniority. He finds this perhaps the greatest moment of his recent life.