**OVERVIEW:** The Cosmos SX-506 Class is a midget submarine operated by the Republic of Korea Navy (ROKN). Commissioned in 1985, these submarines represent an early domestic attempt to develop indigenous submarine capabilities.

**DETAILS:**

The Cosmos SX-506 class was developed in the early 1980s by the Korea Shipbuilding and Engineering Corporation (present-day Korea Shipbuilding & Offshore Engineering). The project emerged from a South Korean desire to acquire independent submarine capabilities, likely driven by the perceived threat from North Korea's submarine forces and a need to patrol coastal waters and support special operations. The design philosophy prioritized a compact and stealthy platform suitable for operating in the shallow and confined waters surrounding the Korean peninsula. The SX-506 class served as a technology demonstrator and training platform, providing the ROKN with invaluable experience in submarine operations and maintenance. It also laid the groundwork for future, more sophisticated submarine programs.

The primary role of the Cosmos SX-506 class was likely coastal patrol and special operations support. Due to their small size, these submarines would have been well-suited for covert insertion and extraction of special forces personnel, reconnaissance missions, and surveillance of North Korean naval activity. While they lack dedicated anti-submarine warfare (ASW) or anti-surface warfare (ASuW) capabilities due to the absence of torpedoes or missiles, their presence would have contributed to the ROKN's overall maritime situational awareness. The boats might also have been used in mine-laying operations, although no explicit evidence supports this. Their shallow draft allowed them to operate in areas inaccessible to larger submarines, enhancing their effectiveness in specific operational scenarios.

The Cosmos SX-506 class is equipped with a generic submarine periscope for visual observation. The periscope provides both a visual search capability and a means for determining range and bearing to surface contacts. The optical periscope allows for real-time visual assessment of the surrounding environment, essential for navigation and target identification. While the precise capabilities of the optical system are unknown, it can be reasonably assumed to include features such as variable magnification and possibly a low-light enhancement mode. The boats lacked sonar or advanced electronic warfare systems, making them reliant on passive acoustic detection and visual observation for situational awareness. The absence of armament limited their offensive capabilities, suggesting a focus on reconnaissance and clandestine operations.

**SPECIFICATION:** Length: 23.0 m || Beam: 2.02 m || Draft: 4.0 m || Disp: 75 t

**SENSORS:** Generic Submarine Periscope, Optical

**ARMAMENT:** None