|Builder:||Vickers Armstrong, Barrow-in-Furness|
|Laid down:||18 September 1941|
|Launched:||24 September 1942|
|Commissioned:||2 February 1943|
|Fate:||sunk 3 October 1943|
|Class and type:||U-class submarine|
|Length:||58.22 m (191 feet)|
|Beam:||4.90 m (16 ft 1 in)|
|Draught:||4.62 m (15 ft 2 in)|
Usurper had a short-lived career with the Royal Navy. During her work-up patrol off the Norwegian coast, she made a torpedo attack on the German submarine U-467. The target was not hit. On being assigned to operate in the Mediterranean, she sank the French ship Château Yquem.
Usurper had left Algiers on 24 September 1943 with instruction to patrol off La Spezia. On 3 October 1943 she was ordered to move to the Gulf of Genoa. No further contact was made and she failed to return to Algiers on 12 October 1943 as expected. The German anti-submarine vessel UJ-2208/Alfred reported attacking a submarine in the Gulf of Genoa on 3 October 1943 and it is believed that this may have been the Usurper.
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