James Madison-Class (SSBN-627) Ballistic Missile Submarines

James Madison-Class (SSBN-627) Ballistic Missile Submarines

The James Madison class, comprising ten nuclear-powered ballistic missile submarines (SSBNs), evolved from the Lafayette class with an initial design modification to accommodate the Polaris A-3 instead of the A-2 missile. This class, completed in 1963-64, led the way for the subsequent Benjamin Franklin class.

James Madison class
Length:425 ft (129.57 m)
Height:32 ft (9.75 m)
Width:33 ft (10.06 m)
Weight:7,320 tons surfaced
8,240 tons submerged
Armament:16 steam ejection tubes for Polaris, Poseidon & Trident missiles and four 21-inch torpedo tubes
Speed:21 knots on the surface
16 knots submerged
Powerplant:Single S5W pressurized water nuclear reactor
Crew complement:147 men; 15 officers, 132 enlisted
Contractors:General Dynamics Electric Boat Division, Mare I NSYd, Newport News, Portsmouth NSYd
Names of submarines:(627) James Madison,
(628) Tecumseh,
(629) Daniel Boone,
(630) John C. Calhoun,
(631) Ulysses S. Grant,
(632) Von Steuben,
(633) Casimir Pulaski,
(634) Stonewall Jackson,
(635) Sam Rayburn,
(636) Nathanael Greene



The James Madison class adopted the SCB-216 design similar to the 616 Class, exhibiting a hull length of 425 feet, a beam of 33 feet, and a draft of 32 feet.

Its surface and submerged displacements escalated to 7,320 and 8,240 tons respectively, primarily due to equipment and machinery modifications inspired by the unfortunate USS Thresher accident. Crew accommodations saw an increase for two additional enlisted men, totaling 132, while the officer count remained constant at fifteen.

Aerial starboard bow view taken in 1983 of USS Casimir Pulaski (SSBN-633)
Aerial starboard bow view taken in 1983 of USS Casimir Pulaski (SSBN-633) (National Archives)

Mirroring the 616 and 627 classes, it sustained a rated speed of over 20 knots when submerged and could dive beyond 400 feet, courtesy of its Thresher hull design.

Following the tragic loss of the USS Thresher off the New England coast during a deep dive test in April 1963, safety protocols were amplified in the construction of the 627 and subsequent classes. The U.S. Navy and submarine builders took this step to prevent a recurrence of such a calamity.


The 627 Class submarines were initially equipped with the Polaris A-3 missile system.

From March 1971 to April 1972, they got upgraded with the Poseidon C-3 missile system and the Mark 88 fire control system during their first overhaul.

USS Ulysses S. Grant (SSBN-631) entering port at Naval Air Station, Barbers Point in Hawaii in 1991
USS Ulysses S. Grant (SSBN-631) entering port at Naval Air Station, Barbers Point in Hawaii in 1991 (National Archives)

Between October 1979 and February 1982, submarines like USS Daniel Boone, USS John C. Calhoun, and USS Stonewall Jackson were updated with the Trident I C-4 missile system.

The same system was installed in the USS James Madison, USS Von Stuben, and USS Casimir Pulaski during their regular overhaul periods, with Daniel Boone becoming operational with the new missiles on September 6, 1980. However, USS Tecumseh, USS Ulysses S. Grant, USS Sam Rayburn, and USS Nathanael Greene didn’t receive the Trident upgrade.


The 627 Class used the same power source as the Lafayette, Ethan Allen, and George Washington Class ships, the Westinghouse S5W water-cooled reactor.

This reactor created 15,000 shaft horsepower, giving energy to the two geared turbines that turn a single seven-bladed propeller.


The 627 Class was equipped with four Mark 65 torpedo tubes, which held Mark 48 multi-use torpedoes.

Starboard-bow view of USS Tecumseh (SSBN-628) in 1986.
Starboard-bow view of USS Tecumseh (SSBN-628) in 1986. (National Archives)

These Mark 48 torpedoes could be controlled by wires or function on their own using active/passive tracking. They could travel more than twenty-three miles and dive deeper than 3,000 feet. Each Mark 48 torpedo weighed 3,520 pounds and carried a 650-pound explosive.

The Mark 113 Mod 9 system was used to control the firing of the torpedoes.

The James Madison Class, following the Lafayette Class, used the Mk 2 Mod 4 Ships Inertial Navigation System (SINS). The 608 Class was equipped with the Mod 3 version, while the 616 Class used the Mod 6 version. All of these submarines had a satellite receiver to get exact navigation details.


On July 19, 1961, six months after accelerating the Lafayette program, President Kennedy approved the construction of 10 enhanced Lafayette submarines, named the James Madison class.

Launching ceremony of the USS Daniel Boone (SSBN-629). (National Archives)

The building of the first submarine, USS Daniel Boone, started on February 6, 1962. These submarines, marked as the 20th through 29th SSBN, were built using the BUSHIPS submarine design SCB-216 Mod 3.

No.NameBuilderKeel LaidLaunchedComm.
SSBN 627James MadisonNewport News5 Mar 196215 Mar 196328 Jul 1964
SSBN 628TecumsehElectric BoatI Jun 196222 Jun 196329 May 1964
SSBN 629Daniel BooneMare I NSYd6 Feb 196222 Jun 196323 Apr 1964
SSBN 630John C. CalhounNewport News14 Jun 196222 Jun 196315 Sep 1964
SSBN 631Ulysses S. GrantElectric Boat18 Aug 19622 Nov 196317 Jul 1964
SSBN 632Von SteubenNewport News4 Sep 196218 Oct 196330 Sep 1964
SSBN 633Casimir PulaskiElectric Boat12 Jan 19631 Feb 196414 Aug 1964
SSBN 634Stonewall JacksonMare I NSYd4 Jul 196230 Nov 196326 Aug 1964
SSBN 635Sam RayburnNewport News3 Dec 196220 Dec 19632 Dec 1964
SSBN 636Nathanael GreenePortsmouth NSYd21 May 196212 May 196419 Dec 1964


The USS Daniel Boone, the first James Madison class submarine to be commissioned, was launched on June 22, 1963, and commissioned on April 23, 1964. A month later, it became the first U.S. FBM to visit Hawaii.

By August, it was based at Apra Harbor, Guam, and started its first deterrent patrol on December 25, 1964.

USS John C. Calhoun (SSBN-630) enters Holy Loch, Scotland in 1991. (National Archives)

Of the James Madison class, four submarines, including Daniel Boone, Tecumseh, Ulysses S. Grant, and Stonewall Jackson, served in the Pacific, while the others were based in the Atlantic.

This arrangement changed with the deployment of Poseidon missiles in March 1971, leading to the transfer of the Pacific-based Lafayette submarines to the Atlantic fleet. By April 1972, Poseidon’s deployment in this class was complete.

In the following table, the details of the conversion to Poseidon are shown:

No.FY ProgramConversion YardStartComplete
SSBN 6271968Electric Boat3 Feb 196928 June 1970
SSBN 6281970Newport News10 Nov 196918 Feb 1971
SSBN 6291968Newport News11 May 196911 Aug 1970
SSBN 6301969Mare I NSYd4 Aug 196922 Feb 1971
SSBN 6311970Puget Sound NSYd3 Oct 196916 Dec 1970
SSBN 6321969Electric Boat11 July 196919 Nov 1970
SSBN 6331970Electric Boat10 Jan 197030 Apr 1971
SSBN 6341971Electric Boat15 July 197029 Oct 1971
SSBN 6351970Portsmouth NSYd19 Jan 19702 Sep 1971
SSBN 6361971Newport News22 July 197021 Sep 1971

On September 6, 1980, eight years post Poseidon conversion, USS Daniel Boone became the first Madison class sub to operate with the Trident I missile, followed by Stonewall Jackson and John C. Calhoun in November.

The James Madison, the Von Steuben, and the Casimir Pulaski received the same upgrade during their second overhaul, completed on June 3, 1983.

Port bow view of USS Stonewall Jackson (SSBN-634) docked in Port Canaveral, Florida in 1994.
Port bow view of USS Stonewall Jackson (SSBN-634) docked in Port Canaveral, Florida in 1994. (National Archives)

After this re-arming, these submarines moved from Rota, Spain, to Kings Bay, Georgia. All Trident I-converted 627 Class FBMs were stationed at Kings Bay Naval Submarine Base, Georgia.

However, for missile loading or unloading, they had to sail to Charleston, S.C., the Atlantic Coast’s Polaris and Trident I missile handling facility. Kings Bay, Georgia, was the Atlantic Coast Strategic Weapons Facility (SWFLANT) for the Trident II D-5 missile system.


In April 1986, the USS Nathanael Greene was grounded in the Irish Sea, sustaining damages that were deemed too extensive for repair, leading to the decision to decommission it.

By March 1987, both the Nathanael Greene and the Sam Rayburn had been taken out of service, with the latter being converted into the first moored training ship (MTS 635) after deactivation and decommissioning.

No.NameDecomm.StrikenBroken up
SSBN 627James Madison20 Nov 199220 Nov 19921997
SSBN 628Tecumseh23 Jul 199323 Jul 19931994
SSBN 629Daniel Boone18 Feb 199418 Feb 19941994
SSBN 630John C. Calhoun28 Mar 199428 Mar 19941994
SSBN 631Ulysses S. Grant12 Jun 199212 Jun 19921993
SSBN 632Von Steuben26 Feb 199426 Feb 19942001
SSBN 633Casimir Pulaski7 Mar 19947 Mar 19941994
SSBN 634Stonewall Jackson9 Feb 19959 Feb 19951995
SSBN 635Sam Rayburn31 Jul 198931 Jul 1989-
SSBN 636Nathanael Greene15 Dec 198631 Jan 19872001

In compliance with the joint U.S./Soviet START Treaty, the USS Tecumseh and the USS Ulysses S. Grant were slated for deactivation by July 1992. By December 1993, Tecumseh, Daniel Boone, John C. Calhoun, Casimir Pulaski, and Stonewall Jackson were placed on stand-down status.

The remaining members of the James Madison class continued to serve but were gradually retired as the newer Ohio Class FBMs were commissioned and started their deterrent patrols at Kings Bay.

Further reading


  • Polmar, N., Moore, K. J. (2014). Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines. United States: Potomac Books, Incorporated.
  • Polmar, N. (1993). The Naval Institute Guide to the Ships and Aircraft of the U.S. Fleet, 15th Edition. United States: Naval Institute Press.
  • Gibson, J. N. (1996). Nuclear Weapons of the United States: An Illustrated History. United States: Schiffer Publishing.
  • Adcock, A. (1993). U.S. Ballistic Missile Subs in Action. United States: Squadron/Signal Publications.
  • Friedman, N. (1995). U.S. submarines through 1945: an illustrated design history. United States: Naval Institute Press.


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Javier Guerrero
Javier Guerrero
Javier is the editor @ Nuclear Companion and loves to investigate and write about the cold war.

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