Najin-class

The Najin-class frigates were for decades the largest combat vessels of the Korean People's Navy. Built in North Korea between 1971 and 1979 at the Najin shipyards, the ships bear a striking resemblance to the Soviet Kola-class frigates but are an unrelated indigenous design. Four or more were completed, of which two remained active into the 2020s, a half-century after commissioning.

Displacing about 1,600 tons for a length of 100 meters, the ships are powered by two diesels totalling 15,000 bhp for a top speed of 26 knots and a range of 4,000 nautical miles at 14 knots, with a crew of around 180. The original armament combined 100 mm and 57 mm guns with a trainable triple torpedo launcher, replaced in the mid-1980s by P-15 Termit anti-ship missile launchers taken from Osa-class missile boats — an arrangement judged inherently dangerous, as even a minor missile failure would cause significant damage to the ship. RBU-1200 anti-submarine launchers, depth charges and mine rails complete the fit.

At least one ship was extensively modernized at Nampo around 2014: the obsolete Termit missiles and aft 57 mm mount were removed in favor of two Kh-35 anti-ship missile racks and two modern 30 mm automated turrets likely derived from the Soviet AK-630 close-in weapon system.