I know this is an old thread - but here is the best history of the Catalpa incident I have yet read. The "Ballad of the Catalpa" is a true folk song - the singing of which was banned by the West Australian Government.
http://www.fremantleprison.com.au/whatson/previousexhibitions/escapefremantletofreedom/Documents/1%20OVERVIEW%20CATALPA.pdf