HMAS J 7.
HMS J7 (later HMAS J7) was a J-class submarine built for the Royal Navy by HM Dockyard Devonport in Plymouth and launched on 12 February 1917.
The submarine's layout differed from the other J class with the control room being placed behind the machinery spaces. This resulted in a changed external appearance with the conning tower 60 feet (18 m) further back compared to other members of the class.
She was transferred to Australia on 25 March 1919 and operated out of Geelong.
J7 paid off on 12 July 1922, was sold on 26 February 1924 and her hulk scuttled on 4 June 1926. Her wreck sits at the bottom of the mini harbour of the Sandringham yacht club in Port Phillip. www.youtube.com/watch?v=gkAE-BlNerY