Keihässalmi was designed according to lessons learned from the Ruotsinsalmi class minelayers, but with increased size and tonnage.

The sinking of the minelayer Riilahti in 1943 had left a big gap in Finnish mine warfare capabilities, and a new vessel was needed.

It would last until the mid-1950s before this was addressed, due to the harsh after-war conditions and war-payments which included many ships to be constructed at Finnish shipyards.

The Keihässalmi was fitted with almost all weapons systems available to the Finnish Navy (except torpedoes), although she primarily was a minelayer and minesweeper.

The Keihässalmi was cheap to operate and required a low complement (important as the Finnish Navy had a manpower restriction), but the vessel proved itself over the decades.