Oberon-class submarine

HMS Otus
Class overview
Name	Oberon
Operators	Royal Navy Royal Australian Navy Royal Canadian Navy Brazilian Navy Chilean Navy
Preceded by	Porpoise class
Succeeded by	Upholder class
In commission	1960-2000
Completed	27
Lost	1
Retired	26
Preserved	10
General characteristics for Royal Navy submarines
Type	Attack/Patrol submarine
Displacement	Surfaced: 2,030 t (2,000 long tons) Submerged: 2,410 t (2,370 long tons)
Length	295.2 ft (90.0 m)
Beam	26.5 ft (8.1 m)
Draught	18 ft (5.5 m)
Propulsion	2 × 3,680 hp Admiralty Standard Range V16 diesels 2 × 3,000 hp electric motors, diesel-electric 2 shafts
Speed	Surfaced: 12 knots (22 km/h) Submerged: 17 knots (31 km/h)
Range	10,350 nautical miles (19,170 km) at surface cruising speed
Test depth	650 ft (200 m)
Complement	7 officers 62 sailors
Sensors and processing systems	Type 1002 surface search and navigation radar Type 187 Active-Passive attack sonar Type 2007 long range passive sonar
Armament	6 × 21 in (530 mm) bow tubes, 20 torpedoes 2 × 21 in (530 mm) short stern tubes, 2 torpedoes Forward torpedo payload could be replaced with 50 × mines
Notes	Taken from. For differing characteristics in non-Royal Navy Oberons, see the Regional variants section

For the 1920s O class submarines, sometimes referred to as the Oberon class, see Odin class submarine.

The Oberon class was a 27-ship class of British-built diesel-electric submarines based on the successful British Porpoise-class submarine. Thirteen were constructed for the Royal Navy, while another fourteen were built and exported to other countries' navies: six to the Royal Australian Navy, three to Canadian Forces Maritime Command (an additional two British submarines were later transferred), three to the Brazilian Navy, and two to the Chilean Navy.

Design and construction

The Oberon class was based heavily on the preceeding Porpoise class of submarines, which were in service from 1956 to 1988. The 295.2 feet (90.0 m) long Oberons were armed with eight 21 inches (1.8 ft) torpedo tubes: six tubes in the bow, and two short tubes for anti-submarine defence in the stern. The submarine normally carried a payload of 20 torpedoes for the forward tubes; a mix of Mark 24 Tigerfish and Mark 8 torpedoes, while only the two pre-loaded torpedoes were carried for the stern tubes. Naval mines could be carried instead of torpedoes: the torpedo payload would be replaced with up to 50 Mark 5 Stonefish or Mark 6 Sea Urchin mines.

Changes from the Porpoise design were primarily to improve the strength and stealth of the submarine. Instead of UXW steel, the hull was built from QT28 steel, which was easier to fabricate and stronger, allowing the submarine to dive deeper. Glass-reinforced plastic was used in construction of the casing.

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.

The Oberons 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. Construction of the British submarines was shared amongst four dockyards: the three mentioned above and Cammell Laird.

Regional variations

Australia

The Royal Australia Navy acquired six Oberons: 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.

Australian Oberons had a different electronic fitout, using primarily American radar and sonar systems. They were equipped with Sperry Micropuffs passive ranging sonar and Krupp CSU3-41 attack sonar. Instead of the British Tigerfish torpedoes, the Australians used American Mark 48 torpedoes. They had a slightly larger payload, carrying 22 torpedoes for the forward tubes, six of which were pre-loaded. Shortly after entering serivce, the aft torpedo tubes in all six submarines were sealed.

The Australian submarines were later updated to be equipped with the subsonic anti-ship 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 sub-surface-launched Harpoon missile, successfully hitting the target from over the horizon. Consequently, the designation for the Austalian Oberons changed from SS to SSG.

Brazil

The main differences between the Brazilian and British Oberons was the fire control systems used; with a Vickers system used. The three Brazilian submarines were later upgraded to use the more advanced Mod 1 Tigerfish torpedo.

Canada

The three Canadian submarines were built with improved air-conditioning systems, while as many common components as possible were replaced with Canadian equivalents. The Canadian Oberons used United States Navy torpedoes throughout their career: they were initially equipped with Mark 37 torpedo, but were later upgraded for Mark 48 torpedoes.

Chile

Chilean submarines were identical to their British counterparts, except for carrying German SUT torpedoes.

Service

The first of the class to be commissioned into the Royal Navy was Orpheus in 1960, followed by the nameship in 1961. The last to be commissioned was Onyx in 1967. Six were commissioned between 1967 and 1978 for the RAN. In 1982, HMS Onyx took part in the Falklands War, the only conventional submarine of the RN to do so, landing members of the SBS. All Oberons in service, including boats exported, have now been decommissioned; the last RN boats were decommissioned in 1993, with the final Canadian and Australian Oberons decommissioned in 2000.

Like the previous Porpoises, the Oberons were far quieter than their American counterparts. They performed remarkably well in clandestine operations, performing surveillance and inserting special forces, vital during their heyday in the Cold War. These operations were primarily carried out by the British across Arctic Europe; the Canadians across the Arctic Pacific; and the Australians throughout south-east Asia and as far north as the Sea of Japan.

The Oberon class was arguably the best conventional submarine class of its time, with an astonishing reputation for quietness that allowed it to exist into the 21st century until replaced by newer classes such as the Collins and Victoria classes in Australia and Canada respectively.

Fates

Two of the British Oberons were transferred to Canada; HMS Olympus as a non-commissioned training ship, and HMS Osiris as a parts hulk.

One of the Brazilian Oberons (S21 Tonelero) sank while docked at the navy yards at the Praça Mauá on Rio de Janeiro, on December 24 2000.

Surviving examples

Helm Station

As of 2006, at least fourteen Oberons are confirmed to have survived in some form. Seven been preserved and converted into museum ships or tourist attractions. Two have been partially preserved as monuments, while another five are awaiting conversion into museum ships, or are otherwise awaiting disposal.

Two of the ex-Royal Navy submarines have now become museum ships in the UK. HMS Onyx has now moved to Barrow-in-Furness after the museum at Birkenhead, Merseyside closed, where another Falklands veteran, HMS Plymouth, has remained. The other boat, HMS Ocelot, is located at Chatham. HMS Otus is harboured in Sassnitz, Germany on the island of Rügen and can be visited.

Australia's six Oberons are located at the following places: HMAS Ovens is located at the Western Australian Maritime Museum at Fremantle, HMAS Onslow is located at the Australian National Maritime Museum in Darling Harbour, Sydney. Both are museum ships. The sail, outer hull, and stern section of HMAS Otway are preserved on land at Holbrook, NSW. HMAS Otama is located at Westernport Bay, Victoria, where she has been awaiting conversion to a museum ship since 2000 - which may now not eventuate due to funding problems. HMAS Oxley’s fin stands as a permanent memorial at HMAS Stirling, Garden Island, Western Australia.

Three former Canadian Forces Oberons are laid up at CFB Halifax. In 2005, Canada announced that it was intending to sell its four surviving Oberons for scrap, as they had deteriorated beyond the point of use as museum ships. However, HMCS Onondaga was acquired in 2006 by the Site historique maritime de la Pointe-au-Père and was towed from Halifax in July 2008 to become a museum ship.

The surviving Brazilian Oberon, S22 Riachuelo, was converted into a museum at the Brazilian Navy Cultural Center (Espaço Cultural da Marinha Brasileira) on Rio de Janeiro.

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 the Canadian Forces after refit as the Victoria class, again replacing Oberons.

The Australian Oberons were replaced by the six Collins class submarines.

The two Chilean Oberons are to be replaced by Scorpène class submarines.

References

• Stevens, David (2001). Stevens, David (ed.). The Royal Australian Navy. The Australian Centenary History of Defence (vol III). South Melbourne, VIC: Oxford University Press. ISBN 0-195-54116-2. OCLC 50418095. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: extra punctuation (link)
• The Encyclopedia of Warships, From World War Two to the Present Day, General Editor Robert Jackson

External links

• Images of HMS Onyx June 2006 being moved to Barrow
• Tour through the S 22 Riachuelo on Rio de Janeiro