Chang Bogo-class (Type 209/1200)

The Chang Bogo class, also designated as KSS-I, is a variant of the Type 209 diesel-electric attack submarine. Named after an ancient maritime figure, the class was developed to serve the requirements of the Republic of Korea Navy and was later adopted by the Indonesian Navy. Since its initial commissioning, the platform has undergone various modifications and has been succeeded by the Type 214. It has also been evaluated for potential acquisition by other regional powers.

This class of attack submarine utilizes a diesel-electric propulsion system. The design features bow-mounted torpedo tubes capable of deploying heavy torpedoes, mines, and integrated anti-ship missiles. Modernization efforts have introduced Torpedo Acoustic Counter Measures and advanced sonar suites, including hull-mounted passive and active search-and-attack arrays. Structural upgrades have involved hull stretching to increase displacement and the development of lithium-ion battery technology to extend submerged endurance. Maintenance protocols require a complete disassembly and re-welding of the hull periodically to replace internal machinery and navigational systems.

The Chang Bogo class is actively operated by South Korea and Indonesia, where it is also known as the Nagapasa class. The platform has been extensively utilized in international maritime exercises, including RIMPAC and Tandem Thrust. Operational records from these simulations indicate high lethality; units have successfully engaged surface vessels and nuclear-powered submarines while remaining undetected. Reported incidents include the sinking of a decommissioned cruiser during a live-fire exercise and a collision with a commercial merchant vessel. The class remains a primary component of regional underwater strike capabilities.