Laid down as the O1 in April 1924 at the Chatham dockyard as a prototype for overseas patrol submarines with a so-called saddle-tank design (used of the Odin-class), she was launched on 24 September 1926, commissioned on 24 August a year later, damaged as a result of a collision with the HMS Thanert on 11 October 1935, decommissioned on 5 July 1944 and laid up at Blyth and a year later sold on 24 August to Clayton and Davies and broken up at Dunston, Tyne and Wear. With a displacement of 1.311 (standard)-1598/1831 (normal) tons were her dimensions 82,19 (over all) x 8,53 x 4,72 (mean normal loaded) or 269’8”x 28’ x 15’6”; Jane‘s Fightings ships 1930 edition reported a displacement of 1.311 *surfaced)-1.805 (submerged) tons. The two shaft diesel engines supplied 2.950 bhp allowing a surfaced speed of 13,75 (design 19) and the electric motors supplied 1,350 bhp allowing a submerged speed of 7,5 (design 9) knots. Her crew numbered 54 men and the armament consisted of 6x2-18” bow torpedo tubes and 2x21” stern torpedo tubes and further more 1-4”quick firing gun and around also 2 smaller guns. Her diving depth was 200 (test)-500 (maximum) feet.
