James Madison-class submarine

The James Madison class of submarine was an evolutionary development from the of fleet ballistic missile submarine. They were identical to the Lafayettes except for being designed to carry the Polaris A-3 missile instead of the earlier A-2. During the late 1970s and early 1980s, select units were further modified to carry Trident-I (C-4) missiles. This class, together with the, , , and classes, comprised the "41 for Freedom."

Class Improvements
Improvements in the James Madison class included the ballistic missile, guidance, fire control, navigation, and launcher systems. The improved missile system introduced was the Polaris A3 missile. The A3 was restricted by size because it had to fit into the existing submarine launch tube. But it was 1.5 in longer, weighed 4000 lbs more, and had a range 1000 nmi farther than the A2. Additionally, the number of reentry systems was increased from 1 to 3, making this the first multiple reentry vehicle missile.

The guidance, fire control, and navigation systems were improved to account for the longer range of the A3 missile. The launcher system was improved by replacing the liquid springs on which the launch tube rested with polyurethane foam.

Boats
Submarines of the James Madison class:
 * USS James Madison (SSBN-627)
 * USS Tecumseh (SSBN-628)
 * USS Daniel Boone (SSBN-629)
 * USS John C. Calhoun (SSBN-630)
 * USS Ulysses S. Grant (SSBN-631)
 * USS Von Steuben (SSBN-632)
 * USS Casimir Pulaski (SSBN-633)
 * USS Stonewall Jackson (SSBN-634)
 * USS Sam Rayburn (SSBN-635)
 * USS Nathanael Greene (SSBN-636)