ships. In December 1943, she sailed to Chatham for a much needed refit. In March 1944, under Lt.Cdr. Trevor Russell-Walling, she carried out her final patrol in the English Channel, when she suffered accidental damage and was docked for repairs. During this time it was decided to convert her as a training boat for anti-submarine warfare operations. The Admiralty had received intelligence in early 1944 about new U-boats which were reported to be able to achieve a top speed of around underwater, compared to the of the fastest existing U-boats. As these new XXI-class U-boats were considered to pose a major threat, Seraph was modified at Devonport as a matter of urgency to have a high underwater speed so that trials and exercises could be carried out against a submarine having a similar underwater speed; for example in developing new tactics. The submarine was streamlined by careful attention to the attachments on the outside of the hull, the size of the bridge reduced, the gun was removed along with one of the periscopes and the radar mast, and torpedo tubes blanked over. The motors were upgraded and higher-capacity batteries fitted along with replacement of the propellers with the coarser pitched type used on the larger T class submarines. Trials and ASW exercises were carried out in September and October 1944, giving an insight into the difficulties and possible remedies to the new underwater menace. After the war Seraph remained in active service after the war. In 1955 she was fitted with armour plating and used as a torpedo target boat. She was attached to a squadron commanded by her first skipper, now Captain David Jewell. Also during this time, Seraph appeared as herself in the British film The Man Who Never Was (1956), which details her exploits during Operation Mincemeat. Her identifying marks are visible in a number of scenes during the film. She remained in commission until 25 October 1962, 21 years to the day after her launching. When she arrived at Briton Ferry for scrapping on 20 December 1962, parts from her conning tower and a torpedo loading hatch were preserved as a memorial at The Citadel in Charleston, South Carolina, where General Clark served as president from 1954–1965. This monument is the only shore installation in the United States where the Royal Navy ensign is authorised to be permanently flown by the British Admiralty. It flies alongside