The SRD used a number of vessels for its operations in South East Asia. Over the course of 1944–45 SRD took control of four trawlers that were constructed at the naval dockyard in Williamstown, Victoria. These vessels were modified with more powerful engines and alterations were made to their superstructures in order to disguise them and make them look more like the types of vessels that were operating in the waters around South East Asia. They were designated "Snake-class" boats. Later, two more were built but they were not completed in time to see service during the war.