Both Tromp-class frigates entered service in 1975/76. Their primary task was area air defence. They acted as flagships for the COMNLTG (Commander Netherlands Task Group).

Because of their large radome (wich housed a 3D radar antenna) the ships had the nickname “Kojak” after the bald-headed actor in the famous action crime tv-series.

The six ‘Roofdier’ class ‘frigates’ were all built in the USA with MDAP funds. They were designed to escort slow coastal convoys in Channel and North Sea areas and were operated as a single squadron by the Royal Netherlands Navy. They proved useful for a number of peacetime tasks, especially fishery protection, and some were retained in this role in the North Sea until die mid-1980s.