KNM Uller was part of the plan to Admiral Schrader, who would lay mines at the entrance to Sognefjord 30 April. Together with Tyr was the plan to put in the sea 80 mines, and effectively block the Norwegian naval force in the country's longest fjord. However, the Norwegian forces has very efficient system of guard ships. The ships, heading for the fjord, were attacked by two of the Royal Norwegian Navy Air Force MF11 patrol. Seaplane dropped nine bombs on the two ships, without damaging any of them, but they hurt three sailors on Uller with shrapnel.
After the ships had fled north, started laying of mines at the entrance to the fjord. In the early hours of 1 May, attacked a seaplane Uller. A simple Norwegian Heinkel He 115 bombed Tyre and Uller, by dropping a 250 kg bomb and four 50 kg bombs with violent opposition from ships. None of the bombs were direct hits, but a bomb-damaged Uller, and caused the sea water flood into. Ulleren had to be put on land, and stranded here. After a while wrecked Uller, as a result of a storm.
Tyre left Uller and retreated south to Bergen, with the crew. Norwegian scouts, however, was still searching for Tyre. Before Tyre reached base, she was attacked in Fålefotsundet between Hisøy and the mainland, by the crew of a Norwegian guard vessel.
Uller is today a beautiful sight with a special type of hull, and with a tall cannon pointing towards the surface. This type of boat is now very uncommon, and only this makes Uller worth a visit. Uller was re found in 2009 and is therefore a unique visit with the past.