Hanwha Ocean launches 3,600-ton-class Seo Hui, bolstering Korean submarine export competitiveness

[Financial News] Hanwha Ocean has launched the 3,600-ton-class latest-generation submarine Seo Hui, built using domestically developed technology. The launch is seen as not only improving operational performance over previous submarines but also further strengthening the technological foundation for competing in overseas submarine markets by localizing 70 types of key equipment.
The Republic of Korea Navy and the Defense Acquisition Program Administration held a launch ceremony on the 3rd at Hanwha Ocean’s Okpo Shipyard in Geoje, South Gyeongsang Province, for Seo Hui (SS-088), the second vessel in the Jangbogo-III Batch-II series. The ceremony took place about five years after Hanwha Ocean signed the construction contract in 2021. Some 200 people attended, including National Assembly Speaker Cho Jeong-sik and officials from the government, military and defense industry.
Seo Hui is the second 3,600-ton-class submarine, following the lead vessel Jang Yeong-sil, which was launched last October. Measuring about 89 meters in length, it has a larger hull than the existing 3,000-ton-class Dosan Ahn Chang-ho-class submarines, expanding its capacity to carry weapons and various types of equipment.
The key is homegrown technology that boosts operational performance. Seo Hui is equipped with a domestically developed lithium battery system, increasing its submerged endurance and the time it can travel at maximum speed compared with previous submarines. The performance of its sonar system, which serves as the submarine’s eyes and ears, and its combat system, which integrates various detection data to support weapons operation, has also been improved, enhancing its ability to detect and identify enemy vessels and carry out precision strikes. Technologies to reduce noise and vibration have also improved stealth, a key competitive advantage for submarines.
Hanwha Ocean additionally localized 12 types of equipment, including the lithium battery system, compared with the Dosan Ahn Chang-ho class. Seo Hui carries a total of 70 types of domestically localized equipment. This is seen as establishing a foundation to reduce reliance on foreign technology and improve the reliability of parts procurement and maintenance, while also addressing requirements for technology transfers or follow-on logistical support during export deals.
Submarines are a major high-value-added class of naval vessel, with demand for maintenance, repair, overhaul and upgrades continuing for decades after construction. If overseas orders are secured, revenue sources can be expanded beyond the initial construction contract through long-term parts supply and maintenance work. This is why analysts say localizing key equipment could strengthen Hanwha Ocean’s business competitiveness over the medium to long term.
Lee Sang-woo, head of the Nuclear-Powered Submarine Program Group at the Defense Acquisition Program Administration, said, “We expect these expanded localization achievements to contribute greatly not only to strengthening the Navy’s capabilities, but also to establishing an advanced defense industry base and expanding submarine exports.”
Seo Hui will be delivered to the Navy in 2028 after sea trials, and is scheduled to enter operational service following its commissioning process.
[email protected] Jung Won-il Reporter