Editing Oberon-class submarine

{{Short description|British-designed underwater naval vessel}}
{{For|the 1920s O class submarines, sometimes referred to as the ''Oberon'' class|Odin-class submarine}}
{{Use dmy dates|date=July 2019}}
{{EngvarB|date=July 2019}}
{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=[[File:HMS Otus 1.jpg|300px|alt=A submarine tied to a dock.]]
|Ship caption={{HMS|Otus|S18|6}} moored at a dock in 2002.
}}
{{Infobox ship class overview
|Name=''Oberon'' class
|Builders=* [[Vickers-Armstrongs]]
* [[Cammell Laird]]
* [[Chatham Dockyard]]
* [[Scotts Shipbuilding and Engineering Company]]
|Operators=* {{Navy|United Kingdom|size=23px}}
* {{Navy|Australia|size=23px}}
* {{Navy|Canada|name=Maritime Command|size=23px}}
* {{naval|Brazil|size=23px}}
* {{Navy|Chile|size=23px}}
|Class before=[[British Porpoise-class submarine|''Porpoise'' class]]
|Class after=[[Upholder/Victoria-class submarine|''Upholder'' class]] and [[Collins-class submarine|''Collins'' class]]
|Cost=
|Built range=
|In service range= 
|In commission range=1960–2000
|Total ships building= 
|Total ships planned=
|Total ships completed=27
|Total ships canceled=
|Total ships active=
|Total ships laid up=
|Total ships lost=
|Total ships retired=27
|Total ships preserved=8 complete, 3 partial, 1 awaiting conversion
}}
{{Infobox ship characteristics
|Header caption=for Royal Navy submarines
|Ship type=Attack/Patrol submarine
|Ship displacement=*Surfaced: {{convert|2030|t|LT|abbr=on}}
*Submerged: {{convert|2410|t|LT|abbr=on}}
|Ship length={{convert|295.2|ft|m|abbr=on}}
|Ship beam={{convert|26.5|ft|m|abbr=on}}
|Ship draught={{convert|18|ft|m|abbr=on}}
|Ship propulsion=* 2 × 1,840&nbsp;hp Admiralty Standard Range V16 diesels
* 2 × 1,280 kW generators
* 2 × 3,000&nbsp;hp electric motors, diesel-electric
* 2 shafts
|Ship speed=* Surfaced: {{convert|12|kn}}<ref name=Janes96>Sharpe (ed.), ''Jane's Fighting Ships, 1996–97'', pgs. 23, 54, 86, 104</ref>
* Submerged: {{convert|17|kn}}<ref name=Janes96/>
|Ship range={{convert|10350|nmi}} at surface cruising speed
|Ship test depth={{convert|650|ft|m|abbr=on}}
|Ship complement=* 7 officers
* 62 sailors
|Ship sensors=* Type 1002 surface search and navigation radar
* Type 187 Active-Passive attack sonar
* Type 2007 long range passive sonar
|Ship EW=MEL Manta UAL or UA4 radar warning{{citation needed|date=November 2011|reason=Equipment appears to have been used on Canadian Oberons, but was it used on British Oberons?}}
|Ship armament=* 6 × {{convert|21|in|mm|1|adj=on|abbr=on}} bow tubes, 20 torpedoes
* 2 × {{convert|21|in|mm|1|adj=on|abbr=on}} short stern tubes, 2 torpedoes
* Forward torpedo payload could be replaced with 50 × mines
|Ship notes=* {{•}}Taken from:<ref name=compedium>Chant, ''A Compedium of Armaments and Military Hardware'', pp. 167–8</ref>
* {{•}}For differing characteristics in non-Royal Navy ''Oberon''s, see the [[#Regional variants|Regional variants]] section or individual submarine articles
}}
|}
The '''''Oberon'' class''' was a [[ship class]] of 27 British-designed [[submarine]]s operated by five nations. They were designed as a follow-on from the [[British Porpoise-class submarine|''Porpoise'' class]]; physical dimensions were the same but stronger materials were used in hull construction and improved equipment was fitted.<ref>{{cite book |last=Chant |first=Christopher |title=Submarine Warfare Today: The World's Deadliest Underwater Weapons Systems |publisher=Silverdale Books |location=Wigston |date=2005 |isbn=1-84509-158-2|oclc=156749009 |page={{page needed|date=June 2015}}}}</ref>

The ''Oberon''s operated during the [[Cold War]], with duties including surveillance, tracking of other ships and submarines, delivery and retrieval of special forces personnel and serving as targets for anti-submarine training. Submarines of the class were in service until 2000.

The ''Oberon'' class was arguably the best conventional submarine class of its time,<ref name="brown&moore"/> with a reputation for remarkable quietness. The quietness of the ''Oberon'' vessels enabled them to operate into the late 20th century until replaced by newer classes such as the [[Collins-class submarine|''Collins'']] and [[Upholder/Victoria-class submarine|''Victoria'']] classes in Australia and Canada, respectively.

The submarines were built between 1957 and 1978 by four shipyards: [[Cammell Laird]] (4), [[Chatham Dockyard]] (6), [[Scotts Shipbuilding and Engineering Company]] (11) and [[Vickers-Armstrongs]] (6).<ref name=Moore>{{cite book |editor=Moore, John |title=Jane's Fighting Ships 1977–78 |edition=80th |year=1977 |series=[[Jane's Fighting Ships]] |publisher=Jane's Yearbooks |location=London |isbn=0531032779 |oclc=18207174 |pages=26, 44, 63, 81, 490}}</ref> Thirteen of the submarines were operated by the [[Royal Navy]], six by the [[Royal Australian Navy]], three by the [[Brazilian Navy]], three by the [[Royal Canadian Navy]]/[[Canadian Forces Maritime Command]] (plus two ex-Royal Navy boats later acquired for non-commissioned roles), and two by the [[Chilean Navy]].<ref name=Moore/>

==Design and construction==
The {{convert|295.2|ft|m|adj=on}}-long ''Oberon'' class was based on the preceding [[British Porpoise-class submarine|''Porpoise'' class]] of submarines, which were in service from 1956 to 1988.<ref name=compedium/> Changes from the ''Porpoise'' design were primarily to improve the strength and stealth of the submarine.<ref name=compedium/> Instead of UXW steel, the hull was built from QT28 steel, which was easier to fabricate and stronger, allowing the submarine to dive deeper.<ref name="brown&moore">Brown & Moore, ''Rebuilding the Royal Navy'', p. 116</ref> [[Glass-reinforced plastic]] was used in construction of the [[casing (submarine)|casing]].

[[File:HMAS Onslow fin and masts.jpg|left|thumb|The fin and equipment masts of {{HMAS|Onslow}}]]
Electronics, sonar, and radar systems were also upgraded to the latest standard. The submarines were equipped with a type 1002 surface search and navigation radar, a type 187 active-passive attack sonar, and a type 2007 long-range passive sonar.<ref name=compedium/> The ''Oberon''s were constructed at a variety of shipyards in the United Kingdom: the six Australian and two Chilean submarines by [[Scotts Shipbuilding and Engineering Company]] (the latter were built after the [[Scott Lithgow]] merger); the three Brazilian submarines by [[Vickers-Armstrongs]]; and the three Canadian submarines at [[Chatham Dockyard]].<ref name=compedium/> Construction of the British submarines was shared amongst four dockyards: the three mentioned above and [[Cammell Laird]].<ref name=compedium/>

===Armament===
{{More citations needed section|date=June 2015}}
[[File:Attack Periscope Type CH74 - RAN Oberon Class Submarine 1957-99.jpg|left|thumb|upright|[[Barr and Stroud]] Attack Periscope Type CH74 – RAN ''Oberon''-class submarine]]

[[File:Fire Control Consoles - HMCS Onondaga.jpg|left|thumb|Torpedo fire control consoles aboard HMCS ''Onondaga'']]

The ''Oberon''s were originally armed with eight {{convert|21|in|mm|1|adj=on}} torpedo tubes: six tubes in the bow, and two short tubes for antisubmarine defence in the stern.<ref name=compedium/> The submarine normally carried a payload of 20 torpedoes for the forward tubes; a mix of [[Mark 24 Tigerfish]] and [[List of torpedoes#21" Mark VIII|Mark 8]] torpedoes, while only the two preloaded [[British 21 inch torpedo#21 inch Mark 20 Bidder|Mark 20S]] torpedoes were carried for the stern tubes.<ref name=compedium/> [[Naval mine]]s could be carried instead of torpedoes: the torpedo payload would be replaced with up to 50 [[Stonefish (mine)|Mark 5 Stonefish]] or Mark 6 Sea Urchin mines.<ref name=compedium/>

The forward torpedo tubes are constructed in two sections bolted together across the bulkhead at the fore end of the torpedo compartment. The {{convert|116|in|cm|adj=on}} long inner section is constructed of {{convert|0.5|in|cm|adj=on}} rolled steel fitted with welded flanges and support brackets.  The outer section is constructed of a similar tube {{convert|175|in|cm}} long but with a reinforced {{convert|1.125|in|cm|adj=on}} thick section behind the main bulkhead. The internal door hinges at one side with two locking mechanisms, a swing bolt opposite the hinge and a rotating locking ring attached to the tube which presses down on the ten projecting lugs around the door. The outer end of the tube is sealed with a domed bow cap. Bow shutters close across the bow caps so as to preserve the streamlined shape of the bow when the cap is closed.

[[File:Ocelot-TorpedoTubes.JPG|right|thumb|Forward torpedo tubes on {{HMS|Ocelot|S17|6}}]]
The bow caps and shutters are mechanically linked to a hydraulically operated drive rod from within the torpedo compartment. The bow cap opens first behind the shutter, which then folds back against it forming a smooth exit tube. Interlocks prevent the doors at both ends being opened at the same time but the inner door is also provided with a test cock to check whether the tube is full of water before opening and remains held nearly closed by the swing bolt after the locking ring is released. The tube internal diameter is 22.5 in, wider than the torpedo, which is designed as a loose fit inside the tube. Torpedoes could be fired either electrically or with compressed air.{{Citation needed|date=February 2024}}

The aft torpedo tubes passed through the ballast tank at the rear of the submarine. A {{convert|31|in|cm|adj=on}} section projected into the boat through the bulkhead, forming overall a relatively short tube of {{convert|12|ft|m}}, but of {{convert|25|in|adj=on}} diameter.

With the retirement of the Mark 20S torpedo in the 1980s, the stern torpedo tubes were decommissioned and the torpedo ballast tanks were thereafter used for storing beer.<ref>{{cite book|title=The Encyclopedia of World Sea Power|page=[https://archive.org/details/encyclopediaofwo0000unse_v9e5/page/42 42]|author=Chris Bishop and Tony Cullen|publisher=Crescent Books|year=1988|isbn=0517653427|url=https://archive.org/details/encyclopediaofwo0000unse_v9e5/page/42}}</ref>

===Propulsion systems===
The class used [[diesel-electric]] propulsion, with [[Lead-acid battery|lead-acid batteries]] to provide power when the engines cannot be used. Each vessel has two Admiralty-pattern V-16 [[diesel engine]]s (ASR1 16VMS), each driving one 1280-kW 880-V [[Electric generator|generator]]. These can provide power directly to the two {{convert|3000|bhp|lk=in|adj=on}} [[electric motor]]s, one directly connected to each [[propeller]], or for charging batteries. The diesel engines can only be operated with external ventilation, but this can be obtained either while on the surface or when shallowly submerged by use of two [[Submarine snorkel|snorkels]] which can be raised from the fin. One snorkel brings in new air to the boat, while the other takes exhaust fumes from the engines. The ventilation system is designed so the fresh air spreads through the boat.<ref name=SFMNPA>{{cite web |title=C.F. 'O' Class Submarines - Electrical Systems |url=https://maritime.org/doc/oberon/electrical/index.php#toc |website=San Francisco Maritime Nation Park Association |access-date=10 June 2024}}</ref>

[[File:HMS Otus - Sassnitz - inside 10.jpg|thumb|right|Engine compartment on {{HMS|Otus|S18|6}}, twin V16 diesel engines]]
The generators are cooled by an internal fan on the shaft which circulates air through a filter and water-cooled heat exchanger within the casing. A grill allows pressure equalisation inside and out. The generator has one pedestal bearing fed with oil from the diesel engine lubrication supply and is fitted with an internal heater to prevent condensation when not running.

The submarine has two batteries, each comprising 224 2V cells (type D7420) giving  a nominal 440&nbsp;V output. One battery is located underneath the crew accommodation compartment, and the other under the control compartment. Each battery has a switch circuit in the middle so it can be split into two banks of 112 cells.  The cells are designed to deliver 7420&nbsp;[[Ampere hour|Ah]] at the five hour discharge rate. All steelwork within the battery compartments is lined with rubber to protect the metal from attack by acid, and also all conducting material is insulated to prevent risks of electric shock. Waxed timber is used to make framing and crawlways to access the batteries and support them because of its resistance to acid. The battery compartment has a [[sump]] to collect any spilled liquids.  Each cell weighs {{convert|1,120|lb|abbr=on}} and contains 18.5&nbsp;gallons of electrolyte. Cells are held tightly in place with wooden wedges to prevent movement with the boat. Each cell has four connector bolts to each electrode and an agitator pipe which bubbles air through the cell to ensure the electrolyte remains mixed and uniform. Cooling water is fed through pipes attached to the electrode connectors to  prevent overheating and the battery temperature is monitored.<ref name=SFMNPA />

In operation, each battery is charged until the voltage reaches 560&nbsp;V, then allowed a further hour's charging. Fortnightly, it should be allowed 5 hours' charging after reaching 560&nbsp;V to ensure a maximum charge is reached. Every two months, the battery should be given an equalising charge of eight hours to ensure all cells have reached their maximum.  The battery is designed to operate with a [[specific gravity]] of the electrolyte between 1.080 and 1.280. Initial charging current should be around 1650&nbsp;amps for s.g. below 1.180, 1250&nbsp;A above 1.180, falling to 280&nbsp;A when charging is complete. At a voltage around 538&nbsp;V, the cells begin to give off explosive [[hydrogen]] gas, so the applied power is reduced during charging to keep voltage below this value until current falls to 280&nbsp;A, which is then maintained while voltage is allowed to rise until  the requisite voltage and charge time are reached. In an emergency, the charging current can be raised to 2000&nbsp;A. To maintain overall capacity, batteries need to be completely discharged over a five-hour period once every four months and then completely recharged. The battery compartments are sealed to prevent gases escaping into the submarine, or salt water entering, which inside a battery would cause the release of poisonous [[chlorine]] gas.  Ventilation fans are used to extract hydrogen released by the cells and catalytic converters are placed strategically through the submarine to remove hydrogen from the air by recombining it with oxygen to form water.<ref name=SFMNPA />

[[File:HMS Ocelot 1962 propellor motor control panel.JPG|thumb|right|Propeller motor control panel: The panel telegraph (top and left) showed instructions issued from the motor telegraph position beside the helm station in the control room which were to be carried out.]]
Each of the two propellers on the submarine is connected to a 3000&nbsp;bhp DC electric motor. Each motor is designed with two separate [[Armature (electrical engineering)|armatures]], in effect two motors in the same unit. Speed of the submarine can be varied by connecting the batteries and armatures in different series and parallel combinations. Slowest speed is obtained by connecting both batteries in parallel, thus supplying 440 V, across all four motor armatures in series, thus applying 110&nbsp;V to each ('shafts in series').  Next, the batteries in parallel may be applied across the two motors in parallel, with their armatures in series ('group down'). This applies 220&nbsp;V across each armature. Third, both batteries are applied in parallel across all four armatures applying 440&nbsp;V to each ('group up'). Finally, the batteries can be arranged in series so as to apply 880&nbsp;V across all four armatures in parallel ('batteries in series'). Each armature also has an associated field winding which is separately supplied with current which may be varied resistively, providing further speed control (maximum 35&nbsp;A).<ref name=SFMNPA />

The motors are designed with a sealed oil [[sump]] from which oil is pumped continuously to lubricate the bearings. A fan draws air from the engine room through the motor to cool it and returns the exhaust air to the engine room through a water-cooled heat exchanger. This arrangement reduces the possibility of water being drawn into the motor should there be a leak in the cooler. The motor is also fitted with a heater to keep it warm when not running so as to prevent condensation internally. Temperature and revolution speed are monitored and displayed on the control panel.<ref name=SFMNPA />

===Auxiliary power===
{{Unsourced section|date=June 2015}}
The batteries provide variable DC power (VP), which ranges in normal usage from 390 to 650 V. Pumps for ballast, water, air compressors, ventilation, cooling, and hydraulics are all designed to cope with this supply range, but some equipment cannot. The boat, therefore, is supplied with two sets of auxiliary motor generators designed to be powered by the batteries and produce stable output, one set powered by each main battery. A 220 V DC supply (CP) is provided by two {{convert|100|kW|abbr=on}} generators, one supplied from each battery with either being sufficient by itself. Two {{convert|15|kW|abbr=on}} 60&nbsp;Hz three-phase alternators provide power for equipment designed to work off 115 or 230 V AC and two more 15&nbsp;kW 400&nbsp;Hz generators provide power at 205 V AC used by radar, sonar, fire control, and communications electronics. Two {{convert|4|kW|abbr=on}} generators plus an additional backup battery provide 24 V DC.

In the event of damage to the main electrical distribution system, provision is made for one of the CP generators to be connected directly to one armature of the port motor, to provide some propulsion by alternative circuitry.<ref name=SFMNPA />

===Regional variations===
[[File:HMAS Oxley bow back.jpg|thumb|left|upright|The preserved bow section of {{HMAS|Oxley|S 57|6}}: The mouths of the six torpedo tubes are displayed, along with the modified sonar dome and a mockup of the bow sonar array.]]
;Australia
:The [[Royal Australian Navy]] acquired six ''Oberon''s: an initial order of four and a second order of two. The second order was originally for four submarines, but two were cancelled in favour of expanding the RAN [[Fleet Air Arm (RAN)|Fleet Air Arm]].<ref name=Stevens194>Stevens (ed.), ''The Royal Australian Navy'', p. 194.</ref>
:Australian ''Oberon''s had different electronic equipment, using primarily American sonar systems. They had [[Sperry Corporation|Sperry]] [[BQG-4]] Micropuffs passive ranging sonar and [[Krupp]] CSU3-41 attack sonar.<ref name=compedium/> Instead of the British Tigerfish torpedoes, the Australians used American [[Mark 48 torpedo]]es.<ref name=compedium/> They had a slightly larger payload, carrying 22 torpedoes for the forward tubes, six of which were preloaded. Shortly after entering service, the aft torpedo tubes in all six submarines were sealed.
:The Australian submarines were later updated to be equipped with the subsonic antiship [[Boeing Harpoon|Harpoon missile]]. In 1985, off the island of [[Kauai]] in [[Hawaii]], HMAS ''Ovens'' became only the second conventional submarine in the world—and the first ''Oberon''—to fire a subsurface-launched Harpoon missile, successfully hitting the target over the horizon. Consequently, the designation for the Australian ''Oberon''s changed from SS to SSG.

;Brazil
:The main differences between the Brazilian and British ''Oberon''s was the fire-control systems, with a Vickers system being fitted to the Brazilian boats.<ref name=compedium/> The three Brazilian submarines were later upgraded to use the more advanced Mod 1 Tigerfish torpedo.<ref name=compedium/>

;Canada
:The three Canadian submarines were built with improved air-conditioning systems, while as many common components as possible were replaced with Canadian equivalents.<ref name=compedium/> The Canadian ''Oberon''s used United States Navy torpedoes throughout their career: they were initially equipped with [[Mark 37 torpedo]]es, but were later upgraded for the [[Mark 48 torpedo|Mark 48s]].<ref name=compedium/>

;Chile
:Chilean submarines were identical to their British counterparts except for carrying German [[SUT torpedo]]es.<ref name=compedium/>

==Service==
===British service===
The first of the class to be commissioned into the Royal Navy was {{HMS|Orpheus|S11|2}} in 1960, followed by the name vessel in 1961. The last to be commissioned was {{HMS|Onyx|S21|2}} in 1967. Six were commissioned between 1967 and 1978 for the RAN. In 1982, ''Onyx'' took part in the [[Falklands War]], the only conventional submarine of the RN to do so, landing members of the [[Special Boat Service|SBS]].{{sfn|Hennessy|Jinks|2015|pp=443-446}} She was escorted back to UK at 5 kn after hitting an undetected submerged reef which damaged two of its torpedo tubes, trapping a [[Tigerfish (torpedo)|Tigerfish]] torpedo. It was removed back at Portsmouth.{{sfn|Hennessy|Jinks|2015|pp=451-452}}

All ''Oberon''s in service, including boats exported, have now been decommissioned; the last RN boats were decommissioned in 1993, with the final Canadian and Australian ''Oberon''s decommissioned in 2000.

===Canadian acquisition===
[[File:Canadian Oberon-class boat alongside in the Caribbean.jpg|thumb|upright|A Canadian ''Oberon''-class submarine alongside in [[Roosevelt Roads Naval Station|Roosey Roads]] for Operation Springboard; January 1969]]
Beginning in 1957, Canada began looking at acquiring submarines to replace the training [[6th Submarine Division]]<ref>{{cite web|last1=Watson|first1=Graham|title=Royal Navy Organisation and Ship Deployment 1947–2013|url=http://www.naval-history.net/xGW-RNOrganisation1947-2013.htm#3|website=naval-history.net|publisher=Gordon Smith, 12 July 2015|access-date=23 March 2017}}
</ref> provided by the Royal Navy at [[Halifax, Nova Scotia]].<ref>Ferguson, p.244</ref> A proposal was submitted to the Canadian Chiefs of Staff in November 1959 affirming the need for a Canadian submarine service and to incorporate the acquisition of the subs into the fleet renewal plan of the late 1950s.<ref>Hadley et al., pp.144–5</ref> The subs would be part of Canada's effort to rectify the problem of block obsolescence in its surface fleet.<ref>Gimblett, p.144</ref> In 1960 two options were presented to the Canadian government, the first suggesting the acquisition of expensive {{sclass|Barbel|submarine|1}}s and the second proposing the purchase of six cheaper ''Oberon''s as part of a larger package of vessels.<ref>Ferguson, p.248</ref><ref>Milner, p.227, 231</ref> In March 1962, [[Cabinet of Canada|Cabinet]] recommended the purchase of three ''Oberon''s and eight frigates, on the condition that the cost of acquiring the submarines from the United Kingdom would be offset by British defence purchases in Canada.<ref>Ferguson, p.249</ref><ref>Hadley et al., p.150</ref> It was also supplement by [[Balao-class submarine]] trainer [[USS Burrfish|HMCS Grilse S-71 (former USS Burrfish SS-312)]] beginning in 1961. On 11 April 1962, the purchase was announced in the [[House of Commons of Canada]] by the [[Minister of National Defence (Canada)|Minister of National Defence]], [[Douglas Harkness]].<ref>Ferguson, p.250</ref><ref>Hadley et al., p.152</ref>

However, the Conservative government postponed the acquisition of the ''Oberon''s due to the slow speed of the United Kingdom's attempt to offset the acquisition.<ref>Ferguson, p.251</ref> The Conservative government was defeated in 1963 and the incoming Liberal government suspended all major defence procurement projects upon taking power.<ref>Ferguson, p.259</ref><ref>Milner, p.237</ref> The United Kingdom, in an effort to get the contract moving, offered the hulls of ''Ocelot'' and ''Opportune'', but Canada passed on them. However, when ''Onyx'' became available, Canada took up the offer. The final price of $40 million for the entire contract was agreed upon in 1963.<ref name=ferguson260>Ferguson, p.260</ref>

Since ''Onyx'' was already under construction, the boat was finished to Royal Navy specifications. All three boats received modifications to the original ''Oberon'' design, which included the enlargement of the snort de-icer, a different weapons fit, a larger air conditioning unit, active sonar and different communications equipment.<ref name=ferguson260/> The second and third hulls were built to Canadian specifications, which moved the galley forward of the control room to make room for the sonar equipment. This led to the removal of three crew bunks, a problem that was never rectified in the submarines and led to an accommodation issue for the crew.<ref>Ferguson, p.263</ref>

The first submarine was scheduled to be delivered in 1965, with the following two in 1967 and 1968, respectively.<ref name=ferguson260/> The three boats were given [[First Nations in Canada|First Nations]] names; ''Onyx'' being renamed ''Ojibwa'', ''Onondaga'' and ''Okanagan''.<ref>Ferguson, p.261</ref> They entered service on 23 September 1965, 22 June 1967 and 22 June 1968 respectively for service as "clockwork mice", submarines used to train surface vessels in anti-submarine warfare.<ref name=mac1>Macpherson and Barrie, p.268</ref><ref>Milner, p.265</ref>

Two further ''Oberon''s were acquired but never commissioned into the Canadian Navy. In 1989, ''Olympus'' was acquired as a stationary [[training ship|training vessel]] at Halifax, Nova Scotia.<ref name=mac1/><ref name=ferguson300>Ferguson, p.300</ref> In 1992 ''Osiris'' was acquired for cannibalisation in a spare parts program between the UK and Canada. The submarine never sailed and was taken apart in the UK to arrive in Canada in 22,050 pieces in 1993.<ref name=ferguson300/>

====Submarine Operational Update Program (SOUP)====
By the late 1970s, the ''Oberon''s in Canadian service had become obsolete and were in need of an update. Planning was done in 1978 and the program approved in February 1979.<ref name=ferguson298>Ferguson, p.298</ref> In an effort to take the subs from anti-submarine warfare training to frontline service, Maritime Command developed a refit program that included new sonars, periscopes, communications and fire-control systems. They also had their armament upgraded with the fitting of torpedo tubes capable of firing the Mk 48 torpedo. This would allow the submarines to be deployed by [[NATO]] in the North Atlantic to monitor Soviet submarines.<ref>Gimblett, p.179</ref><ref>Milner, p.273</ref>

By 1975, the fire control system aboard the Canadian ''Oberon''s was obsolete. Spare parts from the UK were becoming rarer. The Submarine Operational Update Program (SOUP) was developed to deal with the operational capability of the submarines along with a Logistic Support Agreement (LSA) to acquire more spare parts. The SOUP refits were performed during the submarines' mid-life refits.<ref name=ferguson298/> The LSA was finalised in 1989, with the acquisition of ''Olympus'' as a training vessel. However, the LSA was deemed insufficient by 1992 and the Canadian government acquired ''Osiris'' for cannibalisation.<ref name=ferguson300/>

The SOUP refits comprised a new US fire control system, a digital Singer Librascope Mark I, and new Sperry passive ranging sonar with the Type 719 short range sonar removed. The new sonar was placed in the upper casing on the pressure hull. New communications and navigational systems were installed.<ref name=ferguson298/> The submarines were fitted with new torpedo tubes for Mk 48 torpedoes; however, the torpedoes themselves were considered a separate procurement program, which was only finalised in 1985.<ref>Ferguson, pp.298–9</ref>

Between 1980 and 1986, one of the Canadian ''Oberon''s was out of service undergoing the refit. SOUP came in on time and on its budget of $45 million in 1986.<ref>Ferguson, p.299</ref><ref>Milner, p.287</ref> SOUP kept the Canadian ''Oberon''s until the end of the 1990s when they were replaced by the British {{sclass|Upholder|submarine|1}}s.<ref>Gimblett, p.192</ref>

===Chilean service===
[[File:Destroyer Blanco Encalada (DLH 15) and submarine O'Brien (SS 22) .jpg|thumb|right|{{ship|Chilean submarine|O'Brien|S22|6}} operating with the destroyer {{ship|Chilean destroyer|Blanco Encalada|D15|2}} during exercise Teamwork South 1999]]

The Chilean government required two ''Oberon''-class submarines to be built by Scott's Shipbuilders Engineering Co., Ltd. The first  was built in 1971 and launched on 22 December 1972 and given the name ''O'Brien'', arriving at Punta Arenas on 10 August 1976. The second submarine, built in 1972, launched on 26 September 1973, was given the name ''Hyatt''. The submarine arrived at [[Punta Arenas]] on 10 February 1977. These two submarines were able to achieve a speed of 12 knots surfaced and 17 knots submerged. With a length of 90 meters and a displacement of 2,030 tons surfaced and 2,410 tons submerged, the submarines had a 6,000&nbsp;bhp engine to power them. The submarines were fitted with eight 21-inch torpedo tubes. Both submarines remained in service until 31  December 2001 where they were replaced by [[Scorpène-class submarine]]s.

[[File:Hyatt O´Brien and Simpson.jpg|thumb|''Oberon''-class submarines ''Hyatt'' and ''O'Brien'' docked together with the submarine ''Simpson'']]
[[File:Hyatt Submarine.jpg|thumb|''Oberon''-class submarine ''Hyatt'', picture by the Chilean Navy]]

===Australian service===
Australian ''Oberon''-class submarines were reported to have regularly conducted operations with special forces, although due to their limited capability these were restricted to circumstances where the boat could surface, and were usually conducted at night. This included placing divers under the casing for further covert movement, or disembarking special forces teams using kayaks or inflatable boats.<ref>Patrick 2014, p. 37.</ref>

==Fates==
[[File:OberonclassSubmarineHelm.JPG|thumb|left|Helm station aboard {{HMAS|Ovens}} at the [[Western Australian Maritime Museum]]]]
As of 2015, eight of the submarines are preserved intact as [[museum ship|museum vessels]], another three are partially preserved (with some exterior portions of the submarine on display) and one is in private ownership and awaiting conversion for display. The rest have been sold for scrap, including one former museum vessel.

Two of the ex-Royal Navy submarines were preserved in the UK but only one remains. HMS ''Onyx'' was moved to [[Barrow-in-Furness]] after the museum at [[Birkenhead]], [[Merseyside]] closed but was later towed to Gareloch in Scotland where she was broken for scrap in 2014 after failed attempts to turn her into a museum. The other boat, {{HMS|Ocelot|S17|2}}, is located at [[Chatham, England|Chatham]]. {{HMS|Otus|S18|2}} is harboured in [[Sassnitz]], [[Germany]] on the island of [[Rügen]] and can be visited. Another two British ''Oberon''s were transferred to Canada: {{HMS|Olympus|S12|2}} as a non-commissioned training vessel, and {{HMS|Osiris|S13|2}} for [[spare part]]s. The other British submarines were disposed of.

Australia's six ''Oberon''s have been preserved and are on display, either completely or partially. {{HMAS|Ovens}} is located at the [[Western Australian Maritime Museum]] at [[Fremantle]], while {{HMAS|Onslow}} is located at the [[Australian National Maritime Museum]] in [[Darling Harbour]], [[Sydney]]. The [[Fin (submarine)|fin]], outer hull, and stern section of {{HMAS|Otway|S 59|6}} are preserved on land at [[Holbrook, New South Wales]]. {{HMAS|Otama}} is located off [[Crib Point, Victoria|Crib Point]] in [[Western Port|Westernport Bay]], Victoria, where she has been awaiting conversion into a museum vessel since 2002; a lack of funding and co-operation from local and state governments means that the volunteer group hoping to preserve ''Otama'' attempted to sell the submarine on eBay but to no avail.<ref>{{cite web |url=http://www.abc.net.au/news/video/2008/11/24/2427751.htm |title=Former Navy submarine on Ebay |website=[[Australian Broadcasting Corporation]] |format=Streaming video |date=24 November 2008 |access-date=25 November 2008}}<!-- Source expires on 22 February 2009 --></ref> {{HMAS|Oxley|S 57|6}}'s fin stands as a permanent memorial at {{HMAS|Stirling}}, [[Garden Island (Western Australia)|Garden Island, Western Australia]]; while {{HMAS|Oxley|S 57|6}}'s bow is next to {{HMAS|Ovens}} at the [[Western Australian Maritime Museum]]. {{HMAS|Orion}}'s fin stands as a permanent memorial at [[Rockingham Naval Memorial Park]] in Western Australia.

[[File:3 Oberon submarine Dartmouth 2010b.jpg|thumb|right|Three ''Oberon''-class submarines laid up in [[Halifax Harbour]]]]
In 2005, it was announced that the four surviving [[Royal Canadian Navy|Canadian]] submarines (minus ''Osiris'', which was scrapped in 1992{{citation needed|date=July 2011}} after being stripped for parts) were to be sold for scrapping, as they had deteriorated beyond the point of use.<ref name=CBCInDepth>{{cite web |url=http://www.cbc.ca/news/background/cdnsubs/ |title=In Depth: Canada's Submarines |publisher=CBC News |access-date=26 November 2008 |date=1 November 2005<!-- despite being updated during/after 2006 -->}}</ref> {{HMCS|Onondaga|S73|2}} was purchased for C$4 plus tax by the [[Site historique maritime de la Pointe-au-Père]] for use as a museum vessel,<ref name=CBCInDepth/> and was towed from Halifax to [[Pointe-au-Père, Quebec]] in July 2008. In July 2011, ''Olympus'' was towed to a scrapyard in [[Port Maitland, Ontario]], with {{HMCS|Okanagan|S74|2}} to be delivered to the same scrapyard in August 2011.<ref name=Jeffrey>{{cite news |last=Jeffrey |first=Davene |url=http://thechronicleherald.ca/Metro/1253978.html |title=Former HMS Olympus en route to scrapyard  |work=The Chronicle Herald |access-date=20 July 2011 |date=19 July 2011}}</ref> {{HMCS|Ojibwa|S72|2}} has been preserved as part of the [[Elgin Military Museum]].<ref name=Jeffrey/> She was moved to [[Port Burwell, Ontario]] in November 2012, and will become a focal point of a new Museum of Naval History.{{citation needed|date=December 2012}} ''Ojibwa'' opened for public tours in July 2013.

[[File:SS22 Riachuelo.jpg|thumb|SS22 ''Riachuelo'' at the Brazilian Navy Cultural Centre]]
One of the Brazilian ''Oberon''s (''Tonelero'') sank while docked at the navy yards at the [[Praça Mauá]] on Rio de Janeiro, on 24 December 2000.<ref>{{cite web |url=http://jornal.valeparaibano.com.br/2000/12/26/geral/maria.html |title=Submarino da Marinha afunda do Rio<!-- Bot generated title --> |url-status=dead |archive-url=https://web.archive.org/web/20070929090804/http://jornal.valeparaibano.com.br/2000/12/26/geral/maria.html |archive-date=29 September 2007  }}</ref> The surviving Brazilian ''Oberon'', ''Riachuelo'', was converted into a museum at the Brazilian Navy Cultural Center (''Espaço Cultural da Marinha Brasileira'') in Rio de Janeiro.<ref>{{cite web |url=http://www.mar.mil.br/sdm/riachu/riachu.htm |title=Submarino-Museu Riachuelo |language=pt|access-date=26 November 2008 |archive-url = https://web.archive.org/web/20080617112057/http://www.mar.mil.br/sdm/riachu/riachu.htm <!-- Bot retrieved archive --> |archive-date = 17 June 2008}}</ref>

The [[Chilean Navy]] sold {{ship|Chilean submarine|O'Brien||2}} to the city of [[Valdivia]] in 2002, to be converted into the first submarine museum of Chile. The submarine went through a series of modifications in the [[ASMAR]] shipyards during that year, and as of December 2017, is on display at the end of Avenida Costanera Arturo Prat, in front of the [[Law of Chile|Corte de Apelaciones]] building.<ref>{{Cite web|url=http://ccm-valdivia.cl/ccm/index.php/institucion/museo-submarino-o-brien|title=Museo Submarino O'Brien|website=Corporacion Cultural Municipal de Valdivia|access-date=2 February 2018|archive-date=2 February 2018|archive-url=https://web.archive.org/web/20180202223748/http://www.ccm-valdivia.cl/ccm/index.php/institucion/museo-submarino-o-brien|url-status=dead}}</ref><ref>{{cite web|date=25 October 2008|title=O'Brien está listo para carena en Asmar|trans-title=O'Brien is ready for careening in Asmar|author=Juan Vargas O.|url=https://www.australvaldivia.cl/prontus4_nots/site/artic/20081025/pags/20081025000633.html|website=[[Diario Austral]]|language=es}}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

===Successors===
The ''Oberon'' class was briefly succeeded in RN service by the [[Upholder/Victoria-class submarine|''Upholder''-class submarine]]. The ''Upholder''-class submarines were later upgraded and sold to [[Canada]] for service in the [[Royal Canadian Navy]] after refit as the [[Upholder/Victoria-class submarine|''Victoria'' class]], again replacing ''Oberon''s.

The Australian ''Oberon''s were replaced by the six {{sclass|Collins|submarine|1}}s.

The two Chilean ''Oberon''s were replaced by the {{sclass2|Scorpène|submarine|1}}s ''O'Higgins'' and ''Carrera''.

The Brazilian ''Oberon''s were replaced by [[Type 209 submarine]]s.

==See also==
* {{HMS|Oberon|S09|6}}, lead ship of the Oberon class 
* [[List of Oberon-class submarines|List of ''Oberon''-class submarines]]
* [[List of submarines of the Royal Navy]]

==References==

===Citations===
{{reflist|30em}}

===Sources===
* {{cite book|last1=Brown |first1=D.K. |last2=Moore |first2=George |name-list-style=amp |title=Rebuilding the Royal Navy: Warship Design Since 1945 |publisher=Chatham Publishing |year=2003 }}
* {{cite book |last=Chant |first=Christopher |title=A Compendium of Armaments and Military Hardware |url=https://books.google.com/books?id=k9cNAAAAQAAJ |access-date=30 July 2008 |year=1987 |publisher=Routledge |isbn=0-7102-0720-4 }}
* {{cite book |last=Ferguson |first=Julie H. |year=1995 |title=Through a Canadian Periscope: The Story of the Canadian Submarine Service |publisher=Dundurn Press |location=Toronto |isbn=1-55002-217-2 |url-access=registration |url=https://archive.org/details/throughcanadianp0000ferg }}
* {{cite book |editor-last=Gimblett |editor-first=Richard H. |year=2009 |title=The Naval Service of Canada 1910–2010: The Centennial Story |publisher=Dundurn Press |location=Toronto |isbn=978-1-55488-470-4}}
* {{cite book |editor-last=Hadley |editor-first=Michael L. |editor-last2=Huebert |editor-first2=Rob |editor-last3=Crickard |editor-first3=Fred W. |name-list-style=amp |year=1992 |title=A Nation's Navy: In Quest of Canadian Naval Identity |publisher=McGill-Queen's University Press |location=Montreal, Quebec and Kingston, Ontario |isbn=0-7735-1506-2 |url-access=registration |url=https://archive.org/details/nationsnavyinque0000unse }}
* {{cite book |last1=Hennessy |first1=Peter |last2=Jinks |first2=James |title=The Silent Deep |date=2015 |publisher=Allen Lane |isbn=978-1-846-14580-3}}
* {{cite book |editor-last=Jackson |editor-first=Robert |title=The Encyclopedia of Warships, From World War Two to the Present Day}}
* {{cite book |last1=Macpherson |first1=Ken |last2=Barrie |first2=Ron |year=2002 |title=The Ships of Canada's Naval Forces 1910–2002  |edition=Third |publisher=Vanwell Publishing |location=St. Catharines, Ontario |isbn=1-55125-072-1}}
*{{cite journal |last=Patrick |first=Rex |author-link=Rex Patrick |date=September 2014 |title=Submarines and Special Forces |url=http://apdr.realviewtechnologies.com/default.aspx?iid=101338&startpage=page0000020#folio=36 |journal=Asia Pacific Defence Reporter |publisher=Venura Media Asia-Pacific |volume=40 |issue=7 |pages=36–40 |issn=1446-6880 |access-date=6 January 2015 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304030220/http://apdr.realviewtechnologies.com/default.aspx?iid=101338&startpage=page0000020#folio=36 |url-status=dead }}
* {{cite book |editor-last=Sharpe |editor-first=Richard |title=Jane's Fighting Ships, 1996–97 |publisher=Jane's Information Group |location=Surrey |year= 1996 |edition=99th |isbn=0-7106-1355-5 |oclc=34998928 |url-access=registration |url=https://archive.org/details/janesfightingshi0099unse }}
* {{cite book |last1=Stevens |first1=David |last2=Sears |first2=Jason |last3=Goldrick |first3=James |last4=Cooper |first4=Alastair |last5=Jones |first5=Peter |last6= Spurling |first6=Kathryn |name-list-style=amp |editor-last=Stevens |editor-first=David |title=The Royal Australian Navy |series=The Australian Centenary History of Defence |volume=III |year=2001 |publisher=Oxford University Press |location=South Melbourne, Victoria |isbn=0-19-554116-2 |oclc=50418095}}

==External links==
{{Commons category|Oberon class submarines}}
* [https://web.archive.org/web/20120215085053/http://www.photoboxgallery.com/MaritimeAviationNews Images of HMS ''Onyx'' June 2006 being moved to Barrow]
* [https://www.flickr.com/photos/rigues/sets/72157600312501464/ Tour through the S 22 Riachuelo on Rio de Janeiro]
* [http://www.beaconlit.com/cdnsubs.html Through a Canadian Periscope] {{Webarchive|url=https://web.archive.org/web/20081224170156/http://www.beaconlit.com/cdnsubs.html |date=24 December 2008 }} – The story of the Canadian Submarine Service – by Julie H. Ferguson
* [http://maps.google.com.au/maps/ms?hl=en&ie=UTF8&msa=0&msid=113044804882548322551.0004508ad06a472579e4f&t=p&z=2 Location of the Surviving 'O'boats]
* [http://maritime.org/doc/oberon/index.htm C.F. "O" Class Training Handbook for Oberon submarines]
*[https://maps.google.co.uk/maps?q&layer=c&z=17&sll=51.395447,0.526920&cid=17046179510385526206&panoid=D03HgqkhWFIAAAQJOMnFiA&cbp=13,256.06090562598519,,0,0&ved=0CA4Q2wU&sa=X&ei=rHJzUqj3KsnNiAaniYDYDA&gl=GB&hl=en Google Virtual Tour HMS Ocelot at The Historic Dockyard Chatham]

{{Oberon class submarine}}
{{UK submarine classes after 1945}}
{{Chilean submarines}}

[[Category:Submarine classes]]
[[Category:Oberon-class submarines| ]]