South Korea launches first 3,600-ton-class submarine with more missiles

South Korea has launched its largest and most sophisticated submarine to date, the Jang Yeong-sil, marking the beginning of the second batch of its domestically developed KSS-III program.

The vessel, the first of three in this sub-class, stands out for its expanded vertical launch system and a suite of cutting-edge technologies.

The Republic of Korea Navy (ROKN) and the Defence Acquisition Program Administration (DAPA) held the launching ceremony on October 22 at Hanwha Ocean’s Geoje shipyard in southern South Korea, as reported by The War Zone.

A contract for the submarine’s construction was signed in 2019, followed by the steel-cutting ceremony in 2021 and the keel-laying ceremony in 2023.

As the lead vessel of the Batch II submarines, the Jang Yeong-sil builds on the foundation of the KSS-III Batch I, also known as the Dosan Ahn Chang-ho class.

The KSS-III program places South Korea among a small group of nations capable of deploying submarines with submarine-launched ballistic missile (SLBM) capability. Unusually, the South Korean SLBM carries a conventional warhead. Successful underwater ejection tests of the weapon from the first Batch I submarine were reportedly carried out around September of last year.

The Batch II submarines introduce several key differences from their predecessors. They have a surfaced displacement of around 3,500 tons — up from 3,300 tons in Batch I — and measure 293 feet in length, compared to just under 274 feet for the earlier design.

More importantly, Batch II brings what DAPA describes as “enhanced detection, strike capability, stealth, and survivability.”

In terms of detection, the new submarines feature an upgraded combat and sonar system said to deliver improved data processing and target-tracking performance.

The enhanced strike potential centres on expanded land-attack capabilities through its vertical launch system, which allows the submarine to deploy a broader range of weapons.

Stealth and operational endurance are significantly improved thanks to an advanced lithium-ion battery propulsion system. This allows the submarine to “operate underwater for longer durations and sustain high-speed manoeuvres, thereby reducing the risk of exposure during operations.”

While the Jang Yeong-sil remains a diesel-electric submarine, the lithium-ion technology provides performance comparable to — and in some aspects better than — traditional air-independent propulsion (AIP) systems. In addition, the submarine includes a fuel-cell-based auxiliary AIP capability, which enables it to charge its batteries or provide propulsion even while submerged.

According to the article, equally notable is the submarine’s high level of domestic content. The KSS-III Batch II integrates a greater proportion of locally designed and manufactured components, reducing South Korea’s dependence on foreign suppliers and enhancing its potential for export.

The KSS-III design is already being considered for Canada’s new submarine procurement program, which envisions up to 12 vessels, and could attract further interest from countries across the Indo-Pacific and beyond seeking advanced, non-nuclear submarines.

By Nazrin Sadigova