HMS J7
{{short description|Submarine of the Royal Navy}}
{{EngvarB|date=December 2016}}
{{Use dmy dates|date=December 2016}}
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{{Infobox ship image |Ship image = HMAS J7 (AWM H12461).jpg |Ship caption = HMAS J7 }} {{Infobox ship career |Ship country = United Kingdom |Ship flag = {{shipboxflag|United Kingdom|naval}} |Ship name = HMS J7 |Ship ordered = |Ship builder = HM Dockyard, Devonport |Ship yard number = |Ship laid down = |Ship launched = 12 February 1917 |Ship acquired = |Ship commissioned = |Ship decommissioned = |Ship fate = Transferred to Australia, 25 March 1919 }} {{Infobox ship career |Hide header=title |Ship country = Australia |Ship flag = {{shipboxflag|Australia|naval-1913}} |Ship name = HMAS J7 |Ship acquired = 25 March 1919 |Ship commissioned = |Ship decommissioned = 12 July 1922 |Ship fate = Sunk 4 June 1926 |Ship notes=Still extant as breakwater as of 2021 }} {{Infobox ship characteristics |Ship class = British J class submarine |Ship displacement = *{{convert|1210|LT|t}} (surfaced)
|Ship length = {{convert|275|ft|abbr=on}} |Ship beam = {{convert|22|ft|abbr=on}} |Ship draught = {{convert|14|ft|abbr=on}} |Ship propulsion = *Three shafts
|Ship speed = *{{convert|19|kn|abbr=on|lk=in}} (surfaced)
|Ship range = {{convert|4000|nmi|abbr=on}} at {{convert|12|kn|abbr=on}} |Ship endurance = |Ship test depth = {{convert|300|ft|m|abbr=on}} max{{citation needed|date=January 2014}} |Ship complement = 44 personnel |Ship sensors = |Ship EW = |Ship armament = *six 18 inch (450 mm) torpedo tubes
|Ship notes = }} |
HMS J7 (later HMAS J7) was a J-class submarine operated by the Royal Navy and the Royal Australian Navy.
Design and construction
{{Main|J-class submarine}}
The J class was designed by the Royal Navy in response to reported German submarines with surface speeds over {{convert|18|kn}}.Bastock, Australia's Ships of War, p. 86 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. Each submarine was {{convert|275|ft}} in length overall, with a beam of {{convert|22|ft}}, and a draught of {{convert|14|ft}}. The propulsion system was built around three propeller shafts; the J-class were the only triple-screwed submarines ever built by the British. Propulsion came from three 12-cylinder diesel motors when on the surface, and electric motors when submerged. Top speed was {{convert|19|kn}} on the surface (the fastest submarines in the world at the time of construction), and {{convert|9.5|kn}} underwater. Range was {{convert|4,000|nmi}} at {{convert|12|kn}}.
Armament consisted of six 18 inch (450 mm) torpedo tubes (four forward, one on each beam), plus a 4-inch deck gun. 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. The conning tower on J7 was sited {{convert|60|ft|m}} further back than her sister boats, as the control room was located behind the machinery spaces.{{cite book |title=HM Submarines in Camera An Illustrated History of British Submarines |last=Tall |first=J.J |author2=Paul Kemp |year=1996 |publisher=Sutton Publishing |isbn=0-7509-0875-0 |page=54}} 44 personnel were aboard.
J7 was built by HM Dockyard Devonport in Plymouth and launched on 12 February 1917.{{Cite web |title=HMAS J7 |publisher=Royal Australian Navy |url=http://www.navy.gov.au/hmas-j7 |accessdate=2011-03-13 }}
Operational history
After the war, the British Admiralty decided that the best way to protect the Pacific region was with a force of submarines and cruisers. To this end, they offered the six surviving submarines of the J-class to the Royal Australian Navy as gifts. 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 {{HMAS|Sydney|1912|2}} and {{HMAS|Brisbane|1915|2}}, and the tender {{HMAS|Platypus|1917|2}}. The flotilla reached Thursday Island on 29 June, and Sydney on 10 July. Because of the submarines' condition after the long voyage, they were immediately taken out of service for refits.
{{stack|File:HMAS J7 Submarine Sandringham Yacht Club 600 1662.JPG}}
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.
Fate
J7 was paid off on 12 July 1922,{{citation needed|date=September 2021}} and was sold on 26 February 1924{{citation needed|date=September 2021}}. The hulk was scuttled in 1930, for use as a breakwater at the Sandringham Yacht Club in Port Phillip.{{cite news |last1=Callanan |first1=Tim |title=As the spotlight falls on Australia's new submarines, this one is ageing quietly at a Melbourne marina |url=https://www.abc.net.au/news/2021-09-26/this-marina-is-home-to-a-100-year-old-submarine/100442728 |access-date=26 September 2021 |work=ABC News |date=25 September 2021 |language=en-AU}} 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.
Citations
{{Reflist}}
References
- {{cite book |last=Bastock |first=John |title=Australia's Ships of War |year=1975 |publisher=Angus and Robertson |location=Cremorne, NSW |isbn=0207129274 |oclc=2525523}}
External links
- [http://www.syc.com.au/images/marinadir.jpg Map of Sandringham yacht club marina] {{Webarchive|url=https://web.archive.org/web/20080720134524/http://www.syc.com.au/images/marinadir.jpg |date=20 July 2008 }}
{{coord|display=title|-37.943381|144.99471|type:landmark_region:AU}}
{{J-class submarine}}
{{Australian submarines}}
{{DEFAULTSORT:J7}}
Category:British J-class submarines
Category:Ships built in Plymouth, Devon
Category:World War I submarines of the United Kingdom
Category:Scuttled vessels of Australia