In this Thursday, April 19, 2018, photo, Royal Australian Navy frigate HMAS Success prepares to dock at Saigon port in Ho Chi Minh City, Vietnam. It was one of the three Australian Navy ships to make a four-day port call in Vietnam. Australia's Prime Minister Malcolm Turnbull said the Australian navy has a &quot;perfect right&quot; to traverse the South China Sea after a media report Friday that the Chinese navy had challenged three Australian warships in the hotly contested waterway. (Van Khoa/Thanh Nien News via AP)