HMS Gorgon and her sister ship were two monitors originally built as coastal defence ships for the Royal Norwegian Navy, as HNoMS Nidaros and respectively, by Armstrong Whitworth at Elswick. She was purchased from Norway at the beginning of the First World War, but was not completed until 1918 although she had been launched over three years earlier. She engaged targets in Occupied Flanders for the last several months of the war and fired the last shots of the war against such targets on 15 October 1918. She was used as a target ship after several attempts to sell her had fallen through before being sold for scrap in 1928. Background Nidaros was ordered by Norway in 1913 to supplement the older and classes of coastal defense ships. She would have been known in Norway as P/S Nidaros; P/S stands for Panserskip ("armoured ship"), while Nidaros was the old name for the Norwegian city of Trondheim. However, when the First World War broke out, the Royal Navy requisitioned most warships under construction in Britain for foreign powers and refunded the two-thirds of the Bjørgvins £370,000 purchase price already paid by the Norwegians. Construction and description Nidaros was laid down by Armstrong Whitworth at Elswick on 11 June 1913 and launched on 9 June 1914. She was renamed as Gorgon, after an earlier breastwork monitor of 1871. Her completion was greatly delayed by the modifications made by the British, which included modifying the boilers to use both oil and coal and conversion of 12 double-bottom tanks to carry oil. This work began on 9 January 1915, but was suspended the following May, when it was estimated that only another 10–12 months of work remained, to allow for faster progress to be made on the large light cruisers and that were building in Armstrong's Naval Yard downriver. In September 1917, work was resumed on a new design that added a large anti-torpedo bulge along about 75% of the hull's length, suppression of the torpedo tubes and the guns planned by the Norwegians, and a large tripod mast was fitted behind the single funnel to carry the directors for both the and guns. Both of these guns had to be relined to use standard British ammunition and the mount for the 9.2-inch gun was modified to give a maximum elevation of 40° which gave the gun a maximum range of . Addition of