HNoMS Uller was a Vale-class Rendel gunboat constructed for the Royal Norwegian Navy at Karljohansverns Verft Naval Yard in Horten in 1874-1876 and had yard build number 55. She was one of a class of five gunboats - the other ships in the class were Vale, Brage, Nor and Vidar. Uller was, in addition to the heavy, muzzle-loading main gun, armed with a small Quick Fire gun and a 37mm Hotchkiss Revolving Cannon (broadly similar to the Gatling gun). Later Uller and her sister ships were rebuilt as minelayers, and she served in this role when the Germans invaded 9 April 1940.