OVERVIEW: The S 326 Delfinen [UB51] is a submarine operated by the Royal Danish Navy, commissioned in 1975.

DETAILS: The Delfinen was the lead vessel of her class, designed and built to fulfill Denmark's specific requirements for a compact, yet capable, submarine operating primarily in the shallow and constricted waters of the Baltic Sea and Danish straits. The Delfinen class represented a significant step forward for the Royal Danish Navy's submarine capabilities at the time of their introduction, offering a modern platform optimized for anti-submarine warfare (ASW) and surveillance missions. The design prioritized stealth and maneuverability over open-ocean performance, resulting in a relatively small displacement and specialized hull form. The operational doctrine for these boats focused on exploiting littoral environments to mask their presence and effectively engage enemy submarines or surface combatants.

The primary roles of the Delfinen class were ASW and anti-surface warfare (ASuW) within the Baltic and surrounding waters. The Delfinen was well-suited to patrol key chokepoints and conduct covert surveillance operations, providing valuable intelligence to the Danish military and its NATO allies. While not optimized for anti-aircraft warfare (AAW) in the traditional sense, the submarine's stealth capabilities and ability to operate in shallow waters allowed it to pose a credible threat to surface vessels. The deployment of the generic ESM (Electronic Support Measures) suite enables the Delfinen to passively detect and analyze radar emissions from potential threats, providing early warning and situational awareness without revealing its position. Similarly, the generic acoustic intercept system allows the submarine to eavesdrop on enemy communications and sonar activity, further enhancing its intelligence-gathering capabilities.

Technically, the Delfinen’s capabilities were centered around its sonar and torpedo armament. The installation of a generic active/passive attack sonar allows for both the active detection and tracking of targets, and the passive listening for faint acoustic signatures. The generic surface search radar provides a limited surface detection capability for navigation and identifying potential targets at close range while surfaced or snorkeling. The optical submarine periscope, and the added LLTV (Low Light Television) capabilities, permit visual observation in both daylight and low-light conditions, useful for target identification and intelligence gathering. The 533mm torpedo tubes provide a potent offensive capability against both surface and submarine targets. While the specific torpedo types carried are not detailed, this standard NATO-caliber tube would have likely accommodated a range of contemporary guided torpedoes.

SPECIFICATION: Length: 53.9 m || Beam: 4.7 m || Draft: 4.0 m || Disp: 573 t

SENSORS: Generic ESM [Average] || Generic Surface Search Radar || Generic Acoustic Intercept || Generic Active/Passive Attack Sonar || Generic Submarine Periscope, Optical || Generic Submarine Periscope, LLTV

ARMAMENT: 533mm TT