Oberon-class submarine

The Oberon class was a ship class of 27 British-designed submarines operated by five nations. They were designed as a follow-on from the Porpoise class; physical dimensions were the same but stronger materials were used in hull construction and improved equipment was fitted.

The Oberons 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, 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. Glass-reinforced plastic was used in construction of the casing.

left|thumb|The fin and equipment masts of

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.

Propulsion systems

The class used diesel-electric propulsion, with lead-acid batteries to provide power when the engines cannot be used. Each vessel has two Admiralty-pattern V-16 diesel engines (ASR1 16VMS), each driving one 1280-kW 880-V generator. These can provide power directly to the two electric motors, 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 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.

thumb|right|Engine compartment on , 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 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 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 and contains 18.5 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.

:Australian Oberons had different electronic equipment, using primarily American sonar systems. They had Sperry BQG-4 Micropuffs passive ranging sonar and Krupp CSU3-41 attack sonar. provided by the Royal Navy at Halifax, Nova Scotia. 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. The subs would be part of Canada's effort to rectify the problem of block obsolescence in its surface fleet. In 1960 two options were presented to the Canadian government, the first suggesting the acquisition of expensive s and the second proposing the purchase of six cheaper Oberons as part of a larger package of vessels. In March 1962, Cabinet recommended the purchase of three Oberons 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. It was also supplement by Balao-class submarine trainer 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, Douglas Harkness.

However, the Conservative government postponed the acquisition of the Oberons due to the slow speed of the United Kingdom's attempt to offset the acquisition. The Conservative government was defeated in 1963 and the incoming Liberal government suspended all major defence procurement projects upon taking power. 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.

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.

The first submarine was scheduled to be delivered in 1965, with the following two in 1967 and 1968, respectively. 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.

Two further Oberons were acquired but never commissioned into the Canadian Navy. In 1989, Olympus was acquired as a stationary training vessel at Halifax, Nova Scotia. 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. 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.

By 1975, the fire control system aboard the Canadian Oberons 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.

Between 1980 and 1986, one of the Canadian Oberons was out of service undergoing the refit. SOUP came in on time and on its budget of $45 million in 1986. SOUP kept the Canadian Oberons until the end of the 1990s when they were replaced by the British s.

Chilean service

thumb|right| operating with the destroyer 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 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 submarines.

thumb|Oberon-class submarines Hyatt and O'Brien docked together with the submarine Simpson

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.

Fates

thumb|left|Helm station aboard at the [[Western Australian Maritime Museum]]

As of 2015, eight of the submarines are preserved intact as museum vessels, another three are partially preserved (with some exterior portions of the submarine on 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, , is located at Chatham. is harboured in Sassnitz, Germany on the island of Rügen and can be visited. Another two British Oberons were transferred to Canada: as a non-commissioned training vessel, and for spare parts. The other British submarines were disposed of.

Five of Australia's six Oberons have been preserved and are on display, either completely or partially. is located at the Western Australian Maritime Museum at Fremantle, while is located at the Australian National Maritime Museum in Darling Harbour, Sydney. The fin, outer hull, and stern section of are preserved on land at Holbrook, New South Wales. 's fin stands as a permanent memorial at , Garden Island, Western Australia; while 's bow is next to at the Western Australian Maritime Museum. 's fin stands as a permanent memorial at Rockingham Naval Memorial Park in Western Australia.

The only Australian Oberon fully scrapped, , was located off Crib Point in Westernport Bay, Victoria, between 2002 and 2022 where she awaited conversion into a museum vessel; 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. Otama was scrapped in September 2022.

thumb|right|Three Oberon-class submarines laid up in [[Halifax Harbour]]

In 2005, it was announced that the four surviving Canadian submarines (minus Osiris, which was scrapped in 1992 after being stripped for parts) were to be sold for scrapping, as they had deteriorated beyond the point of use. was purchased for C$4 plus tax by the Site historique maritime de la Pointe-au-Père for use as a museum vessel, has been preserved as part of the Elgin Military Museum. 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.

The Chilean Navy sold 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 Corte de Apelaciones building.

Successors

The Oberon class was briefly succeeded in RN service by the 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 Victoria class, again replacing Oberons.

The Australian Oberons were replaced by six s.

The two Chilean Oberons were replaced by the s O'Higgins and Carrera.

The Brazilian Oberons were replaced by Type 209 submarines.

References

Citations

Sources

External links

Images of HMS Onyx June 2006 being moved to Barrow
Tour through the S 22 Riachuelo on Rio de Janeiro
Through a Canadian Periscope – The story of the Canadian Submarine Service – by Julie H. Ferguson
Location of the Surviving 'O'boats
C.F. "O" Class Training Handbook for Oberon submarines
Google Virtual Tour HMS Ocelot at The Historic Dockyard Chatham