O or Oberon Class (1927) SS

The O or Oberon Class (1927) submarines were designed for long endurance operations in the Far East. They were the first class to be identified by names rather than class initial and hull number.

The longer range over that of the previous overseas patrol class,  the L Class (1917), was achieved by fitting  external fuel saddle tanks which had almost 200 tons capacity. Unfortunately they were of riveted construction and suffered from frequent seepage, which revealed the submerged presence of the submarines. 

They had strengthened pressure hulls and had a rated diving depth of 300ft, ram bows and a gun mounted forward of the conning tower.

They were built in three groups, which are sometimes given three different class names.

Group 1 sometimes known as Oberon Class.
Group 2 sometimes known as Oxley Class.
Group 3 sometimes known as Osiris Class.

Group 1 
Was a class of one, HMS Oberon. 

Group 2 
Were two boats (OA1 and OA2) built to a slightly different design for the Royal Australian Navy. Both left Britain for Australia in Feb-1928, but because of a shortage of finance they went into Reserve May-1930. They were commissioned into the Royal Navy as Oxley and Otway in Apr-1931. Later in 1927 a further three boats were laid down for the Chilean Navy.

Group 3 
Were six boats of the same specification as group 1. All laid down in 1927 and commissioned in 1929.

During WW2 HMS Oxley was the first British submarine lost in the war. When she was mistakenly torpedoed by the submarine HMS Triton while outside of her notified patrol area off Obrestad, Norway, 10-Sep-1939. This was the first of two friendly fire incidents between submarines off Norway. The second taking place four days later. After the second one the distance between submarine patrol's off Norway was increased from 4 to 16 miles.  

Five of the nine boats which went to war were sunk by enemy action, three being sunk by Italian destroyers.

In 1942 the survivors were pulled back from frontline duties and used as training boats.

They were all paid off in the late 1940's.


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This page last edited - 08 April, 2013.

Copyright Ian M King, except where otherwise indicated.