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Template:Infobox ship imageTemplate:Infobox ship careerTemplate:Infobox ship careerTemplate:Infobox ship characteristicsHMS J7 (later HMAS J7) was a J-class submarine operated by the Royal Navy and the Royal Australian Navy.
Design and constructionEdit
{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} The J class was designed by the Royal Navy in response to reported German submarines with surface speeds over Template:Convert.<ref name=Bastock86>Bastock, Australia's Ships of War, p. 86</ref> The submarines had a displacement of 1,210 tons surfaced, but J7 had a lighter submerged displacement than her sister boats, at 1,760 tons.<ref name=Bastock86/> Each submarine was Template:Convert in length overall, with a beam of Template:Convert, and a draught of Template:Convert.<ref name=Bastock86/> The propulsion system was built around three propeller shafts; the J-class were the only triple-screwed submarines ever built by the British.<ref name=Bastock86/> Propulsion came from three 12-cylinder diesel motors when on the surface, and electric motors when submerged.<ref name=Bastock86/> Top speed was Template:Convert on the surface (the fastest submarines in the world at the time of construction), and Template:Convert underwater.<ref name=Bastock86/> Range was Template:Convert at Template:Convert.<ref name=Bastock86/>
Armament consisted of six 18 inch (450 mm) torpedo tubes (four forward, one on each beam), plus a 4-inch deck gun.<ref name=Bastock86/> Originally, the gun was mounted on a breastwork fitted forward of the conning tower, but the breastwork was later extended to the bow and merged into the hull for streamlining, and the gun was relocated to a platform fitted to the front of the conning tower.<ref name=Bastock86/> The conning tower on J7 was sited Template:Convert further back than her sister boats, as the control room was located behind the machinery spaces.<ref name=Bastock86/><ref name=tall>Template:Cite book</ref> 44 personnel were aboard.<ref name=Bastock86/>
J7 was built by HM Dockyard Devonport in Plymouth and launched on 12 February 1917.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Operational historyEdit
After the war, the British Admiralty decided that the best way to protect the Pacific region was with a force of submarines and cruisers.<ref name=Bastock86/> To this end, they offered the six surviving submarines of the J-class to the Royal Australian Navy as gifts.<ref name=Bastock86/> J1 and her sisters were commissioned into the RAN in April 1919, and sailed for Australia on 9 April, in the company of the cruisers Template:HMAS and Template:HMAS, and the tender Template:HMAS.<ref name=Bastock86/> The flotilla reached Thursday Island on 29 June, and Sydney on 10 July.<ref name=Bastock86/> Because of the submarines' condition after the long voyage, they were immediately taken out of service for refits.<ref name=Bastock86/>
Template:Stack By the time J7 was returned to service in June 1922, the cost of maintaining the boats and deteriorating economic conditions saw the six submarines decommissioned and marked for disposal.<ref name=Bastock86/>
FateEdit
J7 was paid off on 12 July 1922,Template:Citation needed and was sold on 26 February 1924Template:Citation needed. The hulk was scuttled in 1930, for use as a breakwater at the Sandringham Yacht Club in Port Phillip.<ref name="Callanan">Template:Cite news</ref> Some years later a stone marina was constructed around the wreck, which was left in situ and visible, being too expensive to remove, where it continues to deteriorate.<ref name="Callanan" />
