Korea's Second KSS-III Batch II Submarine "Seo Hui" Launched

According to Naval News, a French maritime publication, on the afternoon of November 3, 2026, the Republic of Korea Navy and the Defense Acquisition Program Administration (DAPA) held the launching ceremony for the second KSS-III Batch II submarine, ROKS Seo Hui (SS-088), at Hanwha Ocean’s Yuseong Shipyard in Goseong, South Korea.

The ROKS Seo Hui is the second submarine in the second batch of the KSS-III program, following the lead vessel ROKS Jang Yeong-sil (SS-087).

The first batch of the KSS-III program comprises three 3,000-ton submarines: ROKS Isan An Chang-ho (SS-083), ROKS Anmoo (SS-085), and ROKS Sin Chae-ho (SS-086). The second batch, designed with a displacement of 3,600 tons, includes the lead vessel ROKS Jang Yeong-sil and the second unit, ROKS Seo Hui.

Korean naval vessels are named after individuals who made significant contributions to military strength, maritime development, technological advancement, or resistance against foreign aggression and independence movements. The choice of naming this vessel after Seo Hui, a prominent official of the Goryeo Dynasty, reflects his distinguished military and diplomatic achievements, as well as his reputation for courage in times of crisis—qualities consistent with the role of this advanced submarine as a core asset in safeguarding national maritime sovereignty.

The ROKS Seo Hui is domestically designed and built. A construction contract was signed in 2021, followed by the steel cutting ceremony that same year, and the keel-laying ceremony in 2024.

The steel cutting ceremony marks the beginning of the shipbuilding process, while the keel-laying signifies the installation of the first major hull section onto the slipway.

The ROKS Seo Hui, the second 3,600-ton submarine of the Republic of Korea Navy, represents a world-class conventional-powered submarine and serves as a critical strategic asset capable of deterring maritime threats around the Korean Peninsula and maintaining robust strategic readiness during emergencies.

Compared to the first batch of the KSS-III, the ROKS Isan An Chang-ho class, the ROKS Seo Hui incorporates the latest shipbuilding technologies, resulting in enhanced capabilities in detection, strike precision, stealth, and survivability.

With an estimated displacement of approximately 3,600 tons and a length of about 89 meters, the vessel features a larger hull than its predecessor, enabling greater capacity for weapons systems and onboard equipment.

The combat system—the submarine’s “brain”—and the sonar system—the “eyes and ears”—have been upgraded, improving the ability to detect multiple targets at long range and conduct precise strikes.

The submarine is equipped with a domestically developed lithium-ion battery system, which has undergone rigorous safety validation. This system extends underwater endurance and sustained operational duration at maximum speed, further enhancing combat effectiveness. Its reliability has been confirmed through multiple safety design measures, dedicated land-based test facilities, and comprehensive safety assessments.

Advanced vibration and noise reduction technologies minimize internal acoustic signatures and mechanical vibrations, contributing to high stealth performance. Survivability has also been strengthened: in the event of primary propulsion failure, an auxiliary propulsion system maintains maneuverability; if optical sensors are compromised, periscopes capable of penetrating the hull allow direct visual observation.

Compared to the first batch’s Isan An Chang-ho class, the ROKS Seo Hui integrates 12 additional types of domestically produced equipment. The total number of indigenous components across the vessel now reaches 70. This domestic content is expected to ensure timely and reliable logistical support while enhancing the export competitiveness of South Korea’s submarine fleet.

Following completion of sea trials, the ROKS Seo Hui is scheduled to be delivered to the navy in 2028 and will enter formal commissioning upon completion of operational capability certification processes.

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Original article: toutiao.com/article/1880877330311172/

Disclaimer: The views expressed in this article are those of the author alone.