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SSBN-640 Benjamin Franklin-Class FBM Submarines

Generally similar to the SSBN-616 Lafayette-class, the twelve Benjamin Franklin (SSBN-640)-class submarines had a quieter machinery design, and were thus considered a separate class.

Lockheed commenced the TRIDENT I (C4) program in November of 1973 with the missile's IOC date established as 1979. The first of the new Ohio-Class submarines was authorized in 1974 but would not be available until 1979. Thus the Navy decided to borrow a page from the Extended Refit Program (ERP) book and a C3 to C4 SSBN "backfit" program was initiated in mid- 1976. The first boat in this SSBN backfit was the Francis Scott Key (SSBN-657). Following the deployment on 20 October 1979 of TRIDENT I (C4) missiles on the Francis Scott, other selected SSBNs were backfitted with the C4 [referred to as follow-on backfits]. Two additional SSBNs of this class (655 and 658) underwent the "pierside backfit" while three others (640, 641, and 643) were backfitted during their normally-scheduled second shipyard overhauls.

Two of these submarines [Kamehameha and James K Polk] were later converted to SEAL-mission capable attack submarines. In March of 1994 USS JAMES K. POLK (SSN 645) completed a 19-month conversion from ballistic missile submarine to attack/special warfare submarine at Newport News Shipbuilding. The January 1999 inactivation of the POLK leaves the KAMEHAMEHA (SSN 642) as the Navy's only former ballistic missile submarine equiped with Dry Deck Shelters (DDSs).

Specifications
Builders:	General Dynamics Electric Boat Division. Mare Island Naval Shipyard Newport News Shipbuilding
Power Plant:	One S5W nuclear reactor two geared steam turbines, 15,000 SHP, one shaft
Length:	425 feet (129.6 meters)
Beam:	33 feet (10.06 meters)
Displacement:	light 6,650 tons standard 7,250 tons submerged 8,250 tons
Speed:	surface: 20+ knots (23+ miles per hour, 36.8 +kph) submerged: 25 knots
Crew:	13 Officers, 130 Enlisted
Armament:	16 - tubes for Polaris and Poseidon 4 - torpedo tubes with Mk48 Torpedoes
Sensors:	BPS-11A or BPS-15 surface-search radar BQR-7 sonar BQR-15 towed-array sonar BQR-19 sonar BQR-21 sonar BQS-4 sonar

Boat List
Boat	Name	Builder	Homeport	Ordered	Commissioned	Decommissioned
SSBN-640	Benjamin Franklin	Electric Boat	Norfolk	01 Nov 62	22 Oct 65	23 Nov 93
SSBN-641	Simon Bolivar	Newport News	Portsmouth	01 Nov 62	29 Oct 65	24 Feb 95
SSBN-642	Kamehameha	Electric Boat	Pearl Harbor	01 Aug 62	10 Dec 65	SSN Jul 92
SSBN-643	George Bancroft	Electric Boat	Charleston	01 Nov 62	22 Jan 66	21 Sep 93
SSBN-644	Lewis and Clark	Newport News	Charleston	01 Nov 62	22 Dec 65	01 Aug 92
SSBN-645	James K Polk	Electric Boat	Norfolk	01 Nov 62	16 Apr 66	08 Jan 99
SSBN-654	George C Marshall	Newport News	Groton	29 Jul 63	29 Apr 66	24 Sep 92
SSBN-655	Henry L Stimson	Electric Boat	Charleston	29 Jul 63	20 Aug 66	05 May 93
SSBN-656	George Washington Carver	Newport News	Groton	29 Jul 63	15 Jun 66	18 Mar 93
SSBN-657	Francis Scott Key	Electric Boat	Charleston	29 Jul 63	03 Dec 66	02 Sep 93
SSBN-658	Mariano G Vallejo	Mare Island NSY	Charleston	29 Jul 63	16 Dec 65	09 Mar 95
SSBN-659	Will Rogers	Electric Boat	Groton	29 Jul 63	01 Apr 67	12 Apr 93
SSBN-				1965	Proposal Cancelled in 1965
SSBN-				1965	Proposal Cancelled in 1965
SSBN-				1965	Proposal Cancelled in 1965
SSBN-				1965	Proposal Cancelled in 1965

Sources and Resources

• Nuclear Submarine Homepages