**OVERVIEW:** The S 40 Riachuelo [Scorpene] is a diesel-electric attack submarine (SSK) in service with the Brazilian Navy, representing a significant upgrade in Brazil's submarine capabilities. Commissioned in 2022, it is the lead boat of the Riachuelo-class, a variant of the French Naval Group's Scorpene design.

**DETAILS:**

The Riachuelo-class submarines represent a cornerstone of Brazil's PROSUB program, an ambitious initiative aimed at bolstering the nation’s indigenous submarine design and construction capabilities. The Scorpene design was selected due to its proven track record and its suitability for adaptation to Brazil's specific operational requirements and the integration of locally produced equipment. The design emphasizes acoustic stealth, making it a challenging target for opposing anti-submarine warfare (ASW) forces. Construction takes place at the Itaguaí shipyard in Brazil, fostering technology transfer and building a national submarine industrial base. The Riachuelo's commissioning marks a key milestone in this program, providing the Brazilian Navy with a modern and potent underwater asset.

The primary roles of the S 40 Riachuelo are anti-submarine warfare (ASW), anti-surface warfare (ASuW), intelligence gathering, and area denial. Its advanced sensor suite allows for effective detection and tracking of both surface and subsurface targets in a variety of operational environments. The submarine can conduct long-range patrols, providing a persistent presence in strategically important areas. Furthermore, it contributes significantly to maritime security and the protection of Brazil's extensive coastline and offshore resources. The platform's versatility makes it a valuable asset for both independent operations and integration into larger naval task forces.

The S 40 Riachuelo is equipped with a comprehensive suite of sensors and weapons optimized for its operational roles. The AR-900S radar provides surface search and navigation capabilities. The TRS 3110 Calypso IV radar, designated DRUA 33 in Brazilian service, offers low probability of intercept (LPI) operation and improved navigation. The TSM 2233M Scylla sonar suite (consisting of the DSUV 2H towed array sonar and the DUUA 2D flank array sonar) provides advanced acoustic surveillance, detection, and classification capabilities, enhancing the submarine's ASW effectiveness. The TSM 2243 fire control system integrates sensor data to provide accurate targeting solutions for its torpedo armament. The Series 30 SMS photonics mast allows for visual observation without compromising the submarine's stealth. The C303/S DL decoy launcher provides a means of defense against incoming torpedoes, enhancing survivability. The 533mm torpedo tubes enable the launch of a variety of modern torpedoes, providing a potent offensive capability against both surface and subsurface targets.

**SPECIFICATION:** Length: 71.6 m || Beam: 6.1 m || Draft: 5.8 m || Disp: 1668 t

**SENSORS:** AR-900S || TRS 3110 Calypso IV [DRUA 33] || TSM 2233M Scylla [DSUV 2H + DUUA 2D] || TSM 2243 || Series 30 SMS Photonics Mast

**ARMAMENT:** C303/S DL || 533mm TT