HMS Annan was a River-class frigate originally constructed for the Royal Navy, but prior to commissioning, she was transferred to the Royal Canadian Navy. Built by Hall, Russell & Co. Ltd. in Aberdeen, Scotland, she was ordered on 26 December 1942, laid down on 10 June 1943, and launched on 29 December 1943. She was commissioned as HMCS Annan on 13 January 1944 after working up at Tobermory. Designed as a convoy escort vessel, Annan primarily operated in the North Atlantic during World War II. She joined escort group EG 6 at Londonderry, where her duties included patrolling and safeguarding convoys in UK coastal waters. A notable achievement occurred on 16 October 1944 when Annan engaged and sank the German submarine U-1006 south of the Faroe Islands, forcing it to surface and subsequently rescuing 46 survivors. In April 1945, her escort group was relocated to Halifax, Nova Scotia, but she returned to the UK in June 1945 and was handed back to the Royal Navy. Following the war, Annan was sold on 22 November 1945 to the Royal Danish Navy, where she was renamed Niels Ebbesen, after the Danish squire Niels Ebbesen. As part of the Danish navy, she was classified within the Holger Danske class and served primarily as a training vessel for naval cadets, accommodating up to 90 trainees. During her Danish service, she underwent several refits to modernize her systems. Niels Ebbesen remained in service until her decommissioning on 8 May 1963. That same year, she was broken up at Odense, Denmark. Throughout her career, the vessel was named after the River Annan in the UK and Canada, and later after Niels Ebbesen in Danish service, marking her as a vessel of maritime significance in escort operations and training roles during and after World War II.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.