The Odin class submarine (or "O class") was a class of nine submarines developed and built for the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 in the 1920s. The prototype was followed by two ships originally ordered for the Royal Australian Navy

Royal Australian Navy

The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...

, but transferred to the RN in 1931 because of the poor economic situation in Australia, and six modified boats ordered for the RN. Three modified ships were built for the Chilean Navy as the Capitan O'Brien-class submarine

Capitan O'Brien class submarine

The Capitan O'Brien class were three submarines built for the Chilean Navy in the late 1920s. They were similar to the contemporary British Odin class submarines, but mounted a larger 4.7 inch deck gun and were slightly smaller.-Ships:...

s in 1929.

Design

They were built to replace the ageing L-class submarine

British L class submarine

The British L class submarine were originally planned under the emergency war programme as an improved version of the British E class submarine. The scale of change allowed the L class to become a separate class....

s which did not have adequate endurance in the Pacific. These boats were theoretically able to dive to 500 feet, though none were formally tested beyond 300 feet. Armament consisted of eight 21-inch torpedo tubes (6 bow, 2 stern) and one 4-inch gun. The boats were of a saddle tank

Saddle tank (submarine)

Saddle tanks are a type of ballast tank configuration fitted to mid-era submarines, those of World War II.Saddle tanks are fitted in pairs external to the pressure hull, one on each side, in a similar manner to that of a horse's saddle-bags, the positioning of which they resemble in appearance.-...

 type with fuel carried in riveted external tanks. These external tanks proved vulnerable to leaking after depth charge

Depth charge

A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

 damage betraying the position of the submarine. These boats were the first British submarines fitted with Asdic and VLF radio which could be used at periscope depth.

Ships

Ship	Builder	Launched	Fate
(ex-O1)	Chatham Dockyard Chatham Dockyard Chatham Dockyard, located on the River Medway and of which two-thirds is in Gillingham and one third in Chatham, Kent, England, came into existence at the time when, following the Reformation, relations with the Catholic countries of Europe had worsened, leading to a requirement for additional...	24 September 1926	Scrapped 1945

Oxley class submarines :

Ship	Builder	Launched	Fate
Otway	Vickers Vickers Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &... , Barrow	7 September 1926	Scrapped 1945
	Vickers, Barrow	29 September 1926	Sunk in a friendly fire Friendly fire Friendly fire is inadvertent firing towards one's own or otherwise friendly forces while attempting to engage enemy forces, particularly where this results in injury or death. A death resulting from a negligent discharge is not considered friendly fire...  incident by near Norway, 10 September 1939

Odin class submarines:

Ship	Builder	Launched	Fate
	Chatham Dockyard	5 May 1928	Sunk by Italian Italy Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...  destroyer Destroyer In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...  Strale Freccia class destroyer The Freccia class destroyer was a class of destroyers built for the Regia Marina, the Italian Royal Navy, in the 1930s. It was basically an enlarged version of the earlier Turbine class destroyers...  in the Gulf of Taranto Gulf of Taranto The Gulf of Taranto is a gulf of the Ionian Sea, in southern Italy.The Gulf of Taranto is almost square, 140 km long and wide, and is delimited by the capes Santa Maria di Leuca and Colonna... , 14 June 1940
	William Beardmore and Company William Beardmore and Company William Beardmore and Company was a Scottish engineering and shipbuilding conglomerate based in Glasgow and the surrounding Clydeside area. It was active between about 1890 and 1930 and at its peak employed about 40,000 people...	11 December 1928	Mined off Malta Malta Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in... , 8 May 1942
	William Beardmore and Company	26 February 1929	Sunk by Italian destroyer Turbine Turbine class destroyer Turbine class was a class of destroyers built for the Italian Regia Marina in the late 1920s. They were essentially larger versions of the earlier .- Turbine class ships :*Aquilone -...  in the Mediterranean, 19 June 1940
	Vickers Vickers Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &... , Barrow	19 May 1928	Scrapped in September 1946 in Durban Durban Durban is the largest city in the South African province of KwaZulu-Natal and the third largest city in South Africa. It forms part of the eThekwini metropolitan municipality. Durban is famous for being the busiest port in South Africa. It is also seen as one of the major centres of tourism... .
	Vickers, Barrow	19 June 1928	Sunk by Italian destroyer Ugolino Vivaldi Navigatori class destroyer The Navigatori class were a group of Italian destroyers built in 1928-29. These ships were named after Italian explorers. They fought in World War II. Just one unit, the Nicoloso Da Recco, survived the conflict.-Design:...  off Calbria, 1 August 1940
	Vickers, Barrow	31 August 1928	Scuttled in September 1946 off Durban.