Buttercup was the first of two corvettes to serve with the Royal Navy Section Belge (RNSB) of the Free Belgian forces, along with HMS Godetia.

She sailed on 13 May 1945 for Oslo carrying the Chief of Staff of the Navy High Command and other naval officers.

Between 2 and 9 September Nordkyn served as a base for a Catalina that the Polarinstitut employed for mapping glacier fronts.

In November 1957 the Norwegian Government sold Nordkyn to Thor Dahl A/S, Sandefjord, a whaling company.

Her new owners had Framnæs Mekaniske Værksted rebuild her, renamed her Thoris, and employed her as a whaler in the Antarctic where she worked with Thor Dahl's whale factory ship.