Laid down at the navy yard at Amsterdam, Netherlands 15 August 1905, launched in the presence of his Royal Highness prince Hendrik 22 September 1906 and commissioned 22 April 1908. The costs of her first fitting out for sea service were ƒ 4.660.000,00. According to the account for the budget year 1910 were the maintenance expenses for the hull ƒ 15.129,73½ and for stores etc. ƒ 134.522,26½. Dimensions 98,00 x 15,20 x 5,70 meters and a displacement of 5.000 tons (as the German Undine decreased to 4.445 tons). The engines provided 6.400 ihp driving two screws allowing a speed of 16,5 miles while she had a coal capacity of 423 tons.The crew numbered 355 men. The armament consisted of 2-24cm guns, 6-15cm guns, 6-7.5cm guns, 4-3.7cm guns and two torpedo tubes.The armament consisted of a 100-150mm belt, 200mm gun turrets, a 50mm deck and a 200mm conning tower. She was commissioned as the floating battery Hr.Ms. IJmuiden 19 April 1939 and scuttled by her own crew at IJmuiden 14 May 1940. Salvaged by the Germans 16 July 1940 and transported 24 July towards Amsterdam and from there 21 March 1941 to Kiel, Germany. There she was at the Howaldtswerke rebuilt as the anti aircraft battery Undine. Her armament consisted now of 8-10.5cm guns, 5-4cm guns and 16-20mm machine guns. After the war she was found back at Wilhelmshafen, Germany and brought back to the Netherlands. At the navy yard at Willemsoord she was rebuilt as an accommodation ship and commissioned as the Hr.Ms. Neptunus 25 February 1948 serving at Den Helder. Her pennant was in the beginning HW 3, later changed into A 881. Later she was slightly rebuilt. Decommissioned 13 September 1974 and stricken 4 October the same year.
