The British government didn’t only transport prisoners to Australia – they also sent prisoners to what was to become the United States in colonial period, particularly to Maryland and Virginia. The American Revolution closed off that option.
In May 1776, the British government created another option: prisoners could be placed on ships. This act, commonly called the “hulks” act, allowed the placement of prisoners on the Thames. It set a precedent of using ships as prisons…
And thus was born the “prison ship” of the American Revolution.
Resources:
“Convict Hulks,” Digital Panopticon (https://www.digitalpanopticon.org/Convict_Hulks: accessed 5 June 2022).
Jeff James, “Prison hulks,” 24 Feb 2012, National Archives (https://media.nationalarchives.gov.uk/index.php/prison-hulks/: accessed 5 June 2022).