55 years ago you would have visited a UK built Oberon class submarine;
The first Australian Oberon class submarine, HMAS Oxley, was commissioned on 21 March 1967. She was followed by her sister ships; Otway (1968), Ovens (1969), Onslow (1969), Orion (1977), and Otama (1978). Orion and Otama were more capable than the previous four boats, as they were fitted with advanced communications monitoring equipment.[12] All of the Oberon class submarines were based at HMAS Platypus, on Sydney Harbor. The Oberons proved very successful and saw extensive service during the last decades of the Cold War.