 By this stage of his career , Waller had acquired a strong reputation for his communications work . In July 1930 , he was posted aboard the Royal Australian Navy 's ( RAN ) flagship , the heavy cruiser HMAS Australia , as squadron signals officer . He continued to perform this role upon transferring to Australia 's sister ship , HMAS Canberra , in May 1931 . In early 1932 , he was assigned to the Navy Office in Melbourne , returning to Canberra as squadron signals officer in August 1933 . He was promoted to commander in June 1934 and the following month became executive officer of the RANC . Departing the college in July 1936 , he returned to England and spent six months working in the British Naval Intelligence Division . A stint as executive officer of the repair ship HMS Resource followed . In November 1937 , Waller was given his first command at sea , the RN destroyer HMS Brazen . His ship handling was criticised early on , but was soon reported by his superiors as having " improved greatly " . Stationed in the Mediterranean , Brazen monitored progress of the Spanish Civil War , a duty that included protecting British merchant vessels and rescuing the crews of sinking ships . By June 1939 , Waller had returned to Australia to become Director of Signals and Communications at the Navy Office . 
