**OVERVIEW:** The A 17 *Södermanland* [Västergötland Mod] is a diesel-electric attack submarine (SSK) operated by the Swedish Navy. The *Södermanland*, along with its sister ship, HMS *Östergötland* (A 18), represents a significant upgrade to the *Västergötland*-class submarines, incorporating advanced technologies and enhancing their operational capabilities.

**DETAILS:**
The *Södermanland* and *Östergötland* underwent a comprehensive modernization program during the early 2000s, extending their service life and significantly improving their performance. Originally built in the late 1980s, the *Västergötland*-class submarines were already considered highly capable for littoral operations. The modification program involved cutting the hull in half and inserting a new section containing Air-Independent Propulsion (AIP) in the form of Stirling engines. This modification dramatically increased submerged endurance, allowing for extended patrol times and reduced vulnerability to detection. The design philosophy behind the upgrade was to create a stealthy and versatile submarine optimized for operations in the challenging Baltic Sea environment. The smaller size of the *Södermanland*-class, compared to nuclear-powered submarines, allows for operations in shallower waters and confined spaces. The class continues to serve as a vital component of Sweden’s maritime defense strategy.

The primary roles of the *Södermanland* are anti-submarine warfare (ASW), anti-surface warfare (ASuW), and intelligence gathering. The submarine's enhanced stealth capabilities, coupled with its advanced sensor suite, make it a formidable ASW platform. It is capable of detecting and tracking enemy submarines in both shallow and deep water environments. In the ASuW role, the *Södermanland* can engage surface combatants with torpedoes and potentially with anti-ship missiles (although this is not explicitly stated, the torpedo tubes provide a potential delivery system). The long endurance provided by the Stirling AIP system further enhances the platform’s ability to maintain a persistent presence in key operational areas. Furthermore, the class undertakes surveillance and reconnaissance missions, using its advanced sensors to gather intelligence on potential adversaries.

The *Södermanland* is equipped with a comprehensive sensor suite designed for optimal performance in the Baltic Sea. The PRS 3-15 passive ranging sonar and CSU 83 sonar provide long-range detection and tracking capabilities. The SUBTASS towed array sonar further enhances its ASW capabilities by providing improved detection ranges and reduced vulnerability to self-noise. The AR-700S5 intercept receiver and TRS 3110 Calypso IV navigation radar, integrated with the DRUA 33, contribute to situational awareness and navigation. The IPS CSU 83 and MAS 83 systems likely provide integrated processing and analysis of sonar data. Two generic submarine periscopes, one optical and one with a low-light television (LLTV) camera, provide visual observation capabilities. This combination of sensors ensures that the *Södermanland* can effectively detect, classify, and engage targets in a variety of operational scenarios.

**SPECIFICATION:** Length: 58.5 m || Beam: 6.1 m || Draft: 5.6 m || Disp: 1150 t

**SENSORS:** PRS 3-15 || CSU 83 || SUBTASS || AR-700S5 || TRS 3110 Calypso IV [DRUA 33] || IPS CSU 83 || MAS 83 || Generic Submarine Periscope, Optical || Generic Submarine Periscope, LLTV

**ARMAMENT:** 533mm TT || 400mm TT || Signal Ejector