In a significant boost to South Korea’s undersea warfare capabilities, Hanwha Ocean has launched the ROKS Jang Yeong-sil (SS-087), the first Dosan Ahn Chang-ho-class KSS-III Batch-II attack submarine for the Republic of Korea Navy. The ceremony took place at the company’s Geoje-si shipyard, marking the start of the next phase in Seoul’s plan to field an indigenously developed and technologically advanced submarine fleet.
The 3,600-ton diesel-electric submarine is a product of South Korea’s expanding defense industrial base, featuring enhanced range, stealth, and combat systems. According to the Navy, the ROKS Jang Yeong-sil will play a vital role in strengthening maritime security across the Korean Peninsula and beyond. The vessel will undergo sea trials and evaluations before joining active service by 2027, enhancing South Korea’s ability to respond to regional threats.
The Batch-II KSS-III submarines boast significant advancements over earlier models, including the integration of lithium-ion batteries for extended underwater endurance and quieter operation. Upgraded sonar arrays, combat systems, and auxiliary propulsion ensure better accuracy, survivability, and operational resilience. The submarine also incorporates low-noise and anti-vibration technology, enabling it to operate stealthily in contested waters.
Built entirely using Korean-designed components, the submarine spans 89 meters in length with a 10-meter beam and can travel 10,000 nautical miles without surfacing, remaining submerged for over 20 consecutive days. Capable of reaching 20 knots, the submarine carries about 50 crew members and is armed with land-attack cruise missiles and submarine-launched ballistic missiles (SLBMs). As part of South Korea’s naval modernization program, nine KSS-III submarines are scheduled for construction by the mid-2030s, following the successful deployment of three Batch-I units between 2021 and 2024.
