OVERVIEW: The Archer [Vastergotland Mod] is a diesel-electric submarine operated by the Republic of Singapore Navy (RSN). It represents a significant upgrade to the ex-Swedish Navy Västergötland-class submarine, providing enhanced capabilities for underwater warfare.

DETAILS:
The Archer-class submarines were originally built for the Swedish Navy as part of the Västergötland class. Singapore acquired two vessels, which underwent extensive modernization before entering RSN service. This modernization program, conducted in Sweden, focused on adapting the submarines to operate effectively in the warmer, shallower waters of the Southeast Asian region and to meet Singapore's specific operational requirements. Key aspects of the upgrade included the installation of a new air-independent propulsion (AIP) system based on Stirling engines, extending the submarine's submerged endurance and reducing its acoustic signature. The acquisition and modernization of the Archer class reflect Singapore's strategic emphasis on maintaining a technologically advanced and regionally relevant submarine force, capable of safeguarding its maritime interests and contributing to regional security.

The primary roles of the Archer-class submarines are anti-submarine warfare (ASW), anti-surface warfare (ASuW), and intelligence, surveillance, and reconnaissance (ISR) operations. The AIP system allows for extended silent running, crucial for ASW operations in detecting and tracking potentially hostile submarines. For ASuW, the Archer is capable of engaging surface combatants with torpedoes. The ISR capability provides the RSN with valuable situational awareness within its area of operations. The vessel's enhanced sensor suite further augments its capabilities in these roles.

The Archer's sensor suite includes the PRS 3-15 passive ranging sonar for long-range detection and classification of underwater targets. The CSU 83 hull-mounted sonar provides active and passive detection capabilities, complemented by the IPS CSU 83 integrated processing system. The SUBTASS towed array sonar significantly extends the submarine's passive detection range. For navigation and target acquisition, the AR-700S5 radar provides surface search capability, while the TRS 3110 Calypso IV [DRUA 33] radar intercept receiver detects and identifies radar emissions from surface vessels and aircraft. The MAS 83 mine avoidance sonar enhances the submarine's safety in mine-threatened waters. Two generic submarine periscopes (one optical, one LLTV) provide visual situational awareness. The vessel is armed with both 400mm and 533mm torpedo tubes, allowing it to employ a variety of torpedoes. A signal ejector allows for covert communication with other units.

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