**OVERVIEW:** The SSBN 640 *Benjamin Franklin* [Improved *Lafayette* Class] is a nuclear-powered ballistic missile submarine (SSBN) operated by the United States Navy. Commissioned in 1981, it represents a late-stage iteration of the *Lafayette*-class SSBNs, incorporating improvements developed throughout the class's service life.

**DETAILS:**
The *Benjamin Franklin*, as an *Improved Lafayette*-class submarine, represents the culmination of lessons learned from earlier SSBN designs. The *Lafayette* class itself was a direct evolution of the *George Washington* and *Ethan Allen* classes, designed to carry the Polaris ballistic missile. The "Improved" *Lafayette* variants, including the *Benjamin Franklin*, underwent significant upgrades focusing on noise reduction, enhanced missile targeting systems, and improved crew habitability. These improvements were crucial for maintaining a credible and survivable nuclear deterrent throughout the Cold War. The adoption of advanced sound dampening techniques made these boats quieter than their predecessors, enhancing their ability to patrol undetected for extended periods. The commissioning of *Benjamin Franklin* in 1981 occurred amidst heightened tensions between the United States and the Soviet Union, making its role in strategic deterrence particularly important.

The primary role of the *Benjamin Franklin* was to provide a survivable, second-strike nuclear capability as part of the United States' strategic triad. This mission necessitated extended deployments in the deep ocean, emphasizing stealth and survivability over offensive capabilities against surface or subsurface threats. While nominally capable of limited self-defense, the primary focus remained on undetected patrol and, if necessary, the delivery of its ballistic missile payload. The 533mm Mk65 torpedo tubes provided a basic anti-submarine warfare (ASW) capability, allowing the vessel to engage trailing submarines in extreme circumstances. The 3-inch Signal Ejector was used for underwater communication and the deployment of countermeasures.

The sensor suite aboard the *Benjamin Franklin* was critical for fulfilling its mission. The AN/BQS-4 sonar provided active detection and ranging capabilities, while the AN/BQR-7 and AN/BQR-15 passive sonar arrays allowed for long-range detection of other vessels by analyzing their acoustic signatures. The AN/BQR-19 towed array sonar offered extended detection range and improved performance in shallow water environments. The AN/WLR-8(V)2 and AN/WLR-9 electronic support measures (ESM) systems detected and analyzed radar emissions from surface ships and aircraft, allowing the submarine to avoid detection. The AN/BPS-15A radar was used for navigation and surface search when the submarine was operating at periscope depth. Both Optical and LLTV periscopes offered visual confirmation of contacts. Finally, the CSA Mk1 FED [Mk139] was used for countermeasures.

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