Hanwha Ocean has launched the Republic of Korea Navy’s first KSS-III Batch-II attack submarine, marking a major step in South Korea’s effort to establish a self-reliant and advanced undersea fleet.
The newly christened ROKS Jang Yeong-sil (SS-087) was unveiled at Hanwha’s Geoje-si shipyard in Gyeongsang Province, attended by senior military and defense officials.
Weighing 3,600 tons, the diesel-electric submarine is expected to enhance maritime defense and deterrence capabilities around the Korean Peninsula, with full fleet induction planned for late 2027 following trials and evaluations.
Enhanced Endurance and Stealth
Compared to earlier Batch-I models, the Jang Yeong-sil boasts greater size, power, and endurance. Its lithium-ion batteries enable longer submerged missions, faster speeds, and a lower acoustic signature, while noise- and vibration-reduction technologies improve stealth.
The submarine is fitted with advanced sonar and combat systems for precise engagement of land and sea targets and includes an auxiliary propulsion system to maintain maneuverability even during main propeller failure.
Indigenous Design and Capability
Developed entirely with domestic technologies, the KSS-III Batch-II measures 89 meters long with a 10-meter beam and can travel 10,000 nautical miles at speeds up to 20 knots, remaining submerged for over 20 days.
It accommodates 50 crew members and carries submarine-launched ballistic and cruise missiles, boosting South Korea’s strategic strike and deterrence posture.
Seoul plans to commission nine KSS-III submarines by the 2030s, three of which—Batch-I units—have already entered service between 2021 and 2024.
