The class was designed at Sparkman & Stephens Inc., New York City, as an improvement of the NYMS class (Norwegian Yard Mine Sweepers).

Five of the vessels were built in the United States, three were built at Westermoen Båtbyggeri og Mek Verksted in Mandal, one at Skaalurens Skibsbyggeri in Rosendal and one at De Forenede Båtbyggerier in Risør.

The class was fully financed by the US government as a part of the Military Assistance Program (MAP).

Most of the vessels were named after Norwegian rivers:Sira, Tana, Alta, Ogna, Vosso, Glomma, Tista, Kvina and Utla.

She is a museum vessel owned by the Royal Norwegian Navy Museum but maintained and sailed by a dedicated friendship association.