OVERVIEW: The 403 Nagapasa [Imp Chang Bogo] is a diesel-electric submarine operated by the Indonesian Navy. The vessel represents a significant upgrade to Indonesia's underwater warfare capabilities and is part of a broader modernization effort.

DETAILS:
The Nagapasa-class submarine, based on the South Korean Chang Bogo-class (a license-built variant of the German Type 209/1200), represents a collaborative effort between South Korea and Indonesia to enhance the latter's naval power. The initial order included submarines built in South Korea followed by licensed construction in Indonesia at the PT PAL shipyard in Surabaya. This arrangement fosters technology transfer and promotes Indonesian self-sufficiency in naval shipbuilding. The design incorporates improvements over the original Type 209, including enhanced sonar systems, improved automation, and a more modern combat management system. The emphasis is on providing Indonesia with a potent, quiet, and cost-effective submarine capable of operating in the challenging archipelagic environment of Southeast Asia.

The primary roles of the 403 Nagapasa are anti-submarine warfare (ASW), anti-surface unit warfare (ASuW), intelligence gathering, surveillance, and reconnaissance (ISR), and sea denial. The submarine's relatively small size and low noise signature make it well-suited for operations in littoral waters, allowing it to effectively patrol strategic straits and choke points. While not designed for anti-air warfare (AAW), its ability to remain undetected significantly enhances its survivability in contested environments. The vessel's diesel-electric propulsion system allows for extended submerged endurance at low speeds, crucial for conducting covert surveillance missions.

The suite of sensors onboard the 403 Nagapasa provides a comprehensive picture of the surrounding maritime environment. The PRS 3-15 active/passive search and attack sonar allows for the detection, classification, and tracking of underwater targets. The CSU 90 hull-mounted and flank array sonars offer enhanced situational awareness and passive ranging capabilities. The IPS CSU 90 integrated processing system further refines sonar data, improving the accuracy and speed of target acquisition. The ARIES-S radar provides surface search and navigation capabilities, while the Pegaso RESM system is crucial for electronic surveillance and intelligence gathering by intercepting and analyzing enemy radar emissions. The OMS 100 / SERO 400 periscope suite provides visual and electro-optical observation capabilities, complemented by laser rangefinding for precise targeting.

SPECIFICATION: Length: 55.9 m || Beam: 6.3 m || Draft: 5.5 m || Disp: 1180 t

SENSORS: PRS 3-15 || CSU 90 Hull || CSU 90 Flank || IPS CSU 90 || ARIES-S || Pegaso RESM || OMS 100 / SERO 400 Periscope Suite

ARMAMENT: 533mm TT