**OVERVIEW:** The SSBN 640 *Benjamin Franklin* [Improved *Lafayette* Class] is a nuclear-powered ballistic missile submarine operated by the United States Navy. Commissioned in 1978, it represents a significant iteration in the US Navy's strategic deterrence program.

**DETAILS:**

The *Benjamin Franklin* represents the improved variant within the *Lafayette* class of ballistic missile submarines. These submarines were designed as the backbone of the United States' sea-based nuclear deterrent during the Cold War. The *Lafayette* class, and the improved variants thereof, were conceived as a direct response to perceived advancements in Soviet anti-submarine warfare (ASW) capabilities. The primary design considerations included minimizing acoustic signature, maximizing submerged endurance, and providing a stable and survivable platform for the delivery of submarine-launched ballistic missiles (SLBMs). The *Benjamin Franklin* featured enhanced quieting technology and improved internal arrangements compared to earlier *Lafayette* boats, further enhancing its ability to evade detection.

The *Benjamin Franklin's* primary role was strategic deterrence, accomplished through the deployment of nuclear-tipped Poseidon C3 ballistic missiles. While not designed for direct engagement of enemy warships, the vessel was equipped with a torpedo capability for self-defense. The vessel did not have a dedicated AAW capability. The submarine's operational profile typically involved extended submerged patrols in strategic areas of the world's oceans, ready to launch its missiles upon presidential order. The focus was on maintaining a credible second-strike capability, ensuring that the United States could retaliate effectively even after absorbing a first strike.

The sensor suite aboard the *Benjamin Franklin* reflected its strategic mission and self-defense requirements. The AN/BQS-4 bow-mounted sonar provided long-range detection and tracking of potential threats, while the AN/BQR-15 passive ranging sonar aided in classifying and localizing targets based on their acoustic signatures. The AN/BQR-7, AN/BQR-19, and AN/BQR-21 sonars provided further refinement of passive detection capabilities. The AN/WLR-8(V)2 and AN/WLR-9 electronic support measures (ESM) systems were critical for detecting and analyzing radar emissions from surface ships and aircraft, providing early warning of potential threats. The AN/BPS-15A surface search radar offered limited surface search capability while surfaced. The installation of two periscopes (Optical and LLTV equipped) allowed for visual observation while at periscope depth. The vessel's self-defense armament included the capability to launch Mk65 torpedoes through its 533mm torpedo tubes and the CSA Mk1 FED [Mk139] Fire control.

**SPECIFICATION:** Length: 129.6 m || Beam: 10.0 m || Draft: 9.6 m || Disp: 7370 t

**SENSORS:** AN/WLR-8(V)2 || AN/BQR-15 || AN/BPS-15A || AN/BQS-4 || AN/BQR-7 || AN/BQR-21 || AN/BQR-19 || AN/WLR-9 || Generic Submarine Periscope, Optical || Generic Submarine Periscope, LLTV

**ARMAMENT:** Poseidon C3 || 3-inch Signal Ejector || CSA Mk1 FED [Mk139] || 533mm Mk65 TT