In Chapter 12 of To Kill a Mockingbird, Atticus has been called to a special session of the Alabama state legislature, of which Atticus is a member representing Maycomb. The Great Depression has also hit the people of Alabama, and there are
... sit-down strikes in Birmingham; bread lines in the cities grew longer, people in the country grew poorer.
The Alabama governor (presumably Bibb Graves, a Democrat who took office in January 1935)
... was eager to scrape a few barnacles off the ship of state...
It can be assumed that since the governor was new, he was ready to enact some new policies or changes, or perhaps make some new appointments. The metaphor about the barnacles (crustaceans which attach themselves to the bottoms of ships and must be removed at certain intervals) being compared to the "ship of state"--the government--suggests that the Governor was ready to "clean house," or at least attempt to clean up some of the problems that were occurring in Alabama.