ROKS Seoae Yu Seong-ryong (DDG-993) is a Sejong the Great-class guided missile destroyer also known as KD-III, commissioned in 2012. The Sejong the Great-class destroyers are three Aegis guided missile destroyers of the Republic of Korea Navy (ROKN). The second ship (ROKS Yulgok Yi I) was commissioned in August 2010 and the third (ROKS Seoae Yu Seong-ryong) in August 2012. As at 2013, the ROKN has deployed three ships with an option for three more; in December 2013 the option to acquire the second three was taken up.
The ship features the Aegis Combat System (Baseline 7 Phase 1) combined with AN/SPY-1D multi-function radar antennae. The Sejong the Great class is the third phase of the South Korean navy’s Korean Destroyer eXperimental (KDX) program, a substantial shipbuilding program, which is geared toward enhancing ROKN’s ability to successfully defend the maritime areas around South Korea from various modes of threats as well as becoming a blue-water navy. At 8,500 tons standard displacement and 11,000 tons full load, the KDX-III Sejong the Great destroyers are by far the largest destroyers in the South Korean Navy, and built slightly bulkier and heavier than Arleigh Burke-class destroyers or Atago-class destroyers to accommodate 32 more missiles. KDX-III are currently the largest ships to carry the Aegis combat system.
ROKS Seoae Yu Seong-ryong main gun is the 127 mm/L62 Mk. 45 Mod 4 naval gun, an improved version of the same gun used on other warships from several foreign nations. Point-defense armaments include one 30 mm Goalkeeper CIWS and a RIM-116 Rolling Airframe Missile Block 1 21-round launcher, the first Aegis platform to carry RAM. Anti-aircraft armament consists of SM-2 Block IIIA and IIIB in 80-cell VLS. Anti-submarine warfare armaments consists of both K-ASROC Hong Sahng-uh (Red Shark) anti-submarine rockets and 32 K745 LW Cheong Sahng-uh (Blue Shark) torpedoes. Anti-ship capability is provided by 16 SSM-700K Hae Sung (Sea Star) long-range anti-ship missile, each with performance similar to the U.S. Harpoon. Land-attack capability is provided by the recently developed Hyunmoo-3C (Guardian of the Northern Sky) cruise missile, which is similar to the U.S. Tomahawk.