Ulsan-class

The Ulsan-class frigate was developed for the Republic of Korea Navy as the high-end component of a high-low mix domestic naval construction program. This initiative occurred under the 1st Yulgok Project between 1974 and 1986. Construction was shared among Hyundai Heavy Industries, Korea Shipbuilding Corporation, Korea Tacoma Shipyard, and Daewoo Shipyard.

The class consists of light frigates produced in three batches. The propulsion system utilizes a Combined Diesel or Gas (CODOG) configuration, incorporating GE LM2500 gas turbines and MTU diesel engines. Sensor suites vary by batch; Batch I and II units utilize the Signaal SEWACO ZK fire control system, while Batch III vessels use the Samsung/Ferranti WSA-423. Underwater detection is provided by Signaal hull-mounted sonar and TB-261K towed sonar. Electronic warfare equipment includes the ULQ-11K suite, Mark 36 SRBOC launchers, and SLQ-261 torpedo acoustic countermeasures. Armament includes OTO Melara cannons, Harpoon anti-ship missiles, and Mark 32 surface vessel torpedo tubes. Secondary gun systems differ between variants, with Batch I vessels carrying Emerson EMERLEC units and subsequent batches employing Breda DARDO systems.

The Republic of Korea Navy commissioned nine Ulsan-class vessels between 1981 and 1992. ROKS Ulsan, the lead ship, entered service in January 1981 and was decommissioned in 2014. Two vessels, ROKS Busan and ROKS Cheongju, remain active. Several retired hulls have been repurposed; ROKS Ulsan, ROKS Seoul, and ROKS Masan serve as museum ships in Ulsan, Seoul, and Gangwha Island. Other decommissioned units, such as ROKS Chungnam and ROKS Gyeongbuk, function as reserve or training vessels. The Argentine Navy was offered ROKS Chungnam but declined the transfer. In 2001, the Bangladesh Navy commissioned the BNS Khalid Bin Walid, a modified variant of the design. The Incheon class succeeded the Ulsan class in South Korean service.