OVERVIEW: The SSN 671 *Narwhal* is a unique submarine of the United States Navy, designated as a nuclear-powered attack submarine (SSN). While outwardly resembling the *Sturgeon*-class, it incorporated significant internal modifications and served primarily as a technology demonstrator and platform for advanced research.

DETAILS:
The *Narwhal* was authorized in 1966 and commissioned in 1978, representing a significant deviation from contemporary U.S. submarine design philosophy. Its most notable feature was the S5G natural circulation reactor, intended to operate with significantly reduced noise compared to forced-circulation reactor designs prevalent at the time. The natural circulation reactor, while ultimately proving successful, was an experimental design intended to contribute to the Silent Service's underwater stealth capabilities. The *Narwhal's* construction and operational profile were heavily influenced by the drive to improve acoustic performance, placing it at the forefront of submarine quieting efforts during the Cold War. This focus on acoustic signature mitigation influenced not only the reactor design but also various aspects of the hull design and internal machinery layout.

The *Narwhal*'s primary roles, despite its experimental nature, included anti-submarine warfare (ASW), anti-surface warfare (ASuW), and intelligence gathering. Although primarily a technology demonstrator, it remained a fully operational attack submarine, participating in fleet exercises and deployments throughout its career. The installation of the AN/BQQ-5A(V)2 sonar suite, potentially incorporating the BQS-12 passive ranging sonar, provided advanced detection and tracking capabilities against both surface and subsurface targets. The AN/BRD-6 direction finding equipment allowed for the identification and location of radio transmissions, crucial for intelligence gathering. While details of its operational history are scarce due to the classified nature of its missions, it is known that *Narwhal* was frequently deployed on sensitive missions leveraging its quiet operation.

Technologically, the *Narwhal* was equipped with a comprehensive suite of sensors. The AN/TB-16 towed array provided extended-range passive sonar detection, crucial for detecting quiet enemy submarines. The AN/BQS-14 and AN/BPS-14 radars likely served for navigation and surface detection, respectively. The AN/WLR-9 electronic support measures (ESM) system enabled the submarine to detect and analyze radar emissions from enemy ships and aircraft. The two generic submarine periscopes, one optical and the other incorporating a low-light television (LLTV) camera, facilitated visual observation in both daylight and low-light conditions. The armament of 533mm Mk67 torpedo tubes allowed for the deployment of Mk48 torpedoes or other compatible ordnance, providing a potent offensive capability. The 3-inch signal ejector would be used for launching flares and other countermeasures.

SPECIFICATION: Length: 96.0 m || Beam: 9.7 m || Draft: 8.8 m || Disp: 5027 t

SENSORS: AN/TB-16 || AN/BQS-14 || AN/BPS-14 || AN/BQQ-5A(V)2 [BQS-12] || AN/BRD-6 || AN/WLR-9 || Generic Submarine Periscope, Optical || Generic Submarine Periscope, LLTV

ARMAMENT: 533mm Mk67 TT || 533mm Mk67 TT || 3-inch Signal Ejector