The USS Jimmy Carter (SSN 23),  a modified Seawolf-class submarine, is used for missions the navy does not like to talk about. The Carter displaces 12,151 tons submerged, is 100 feet longer than a baseline Seawolf (453 feet compared to 353 feet). She is also slightly slower than a baseline Seawolf (61.1 kilometers per hour compared to 64.8 for the baseline Seawolf), and carries the same armament (eight 30-inch torpedo tubes with fifty weapons).

The Jimmy Carter, though, was not designed  for combat patrols. She is officially a testbed, much like the Los Angeles-class submarine USS Memphis. However, her real role is to eventually replace the Sturgeon-class submarine USS Parche, which was taken out of service in October, 2004. The USS Parche also has a 100-foot long extension although that was installed during a refit that lasted from 1987-1991. The Navy is very reluctant to give out details about the Jimmy Carter, and she is often placed in a covered drydock (to keep her away from prying eyes in space as well as on the ground). This is not surprising. The methods and sources of intelligence are protected very closely by the intelligence community, and the Jimmy Carter is going to be one of the prime sources of intelligence.

The Jimmy Carter is capable of carrying 50 special operations personnel, but her primary mission will be intelligence gathering. The Navy doesnt talk much about the intelligence-gathering missions it has carried out in the past, or currently. One of the missions Parche carried out was the maintenance of taps on undersea phone lines between the Russian naval bases of Petropavalosk and Vladivostok (the famous Ivy Bells mission). Other missions involved electronic intelligence. Submarines are ideal for this mission they can often supplement coverage by aircraft and satellites. This supplementary coverage it vital. Aircraft can be detected and have limited range and satellites have predictable orbits. Dummy transmissions can be used to throw them off. Submarines, on the other hand, are unpredictable things particularly nuclear-powered submarines. There is no way to know a submarine is there unless it either chooses to reveal its presence (usually through the creation of a flaming datum) or something goes wrong (a collision like which happened with the USS Tautog). Submarines often get data on new naval units often shadowing them and collecting hull shots (pictures of the hull of a ship or submarine) and a very good idea of the ships acoustic signature (for future identification).

In time of war, the Jimmy Carter will provide support for various missions, like raids by SEALs and other special operations units. Often, these groups will split up for missions, which could run the gamut of raids or advising partisans, or a single large mission could be carried out. Often, their delivery will be by the Advanced SEAL Delivery System, supported in a Dry Dock Shelter. She will also have additional command and control facilities, and storage for additional munitions and fuel.

You will not hear much about what the Jimmy Carter does if the United States Navy has its way. The submarines are called the Silent Service. This is doubly true for those submarines like Jimmy Carter and Parche which engage in intelligence gathering. Their successes remain secret failures will probably make the press. 

Comparison of special operations subs Jimmy Carter and Parche. Seawolf 
included for comparison to Carter. Harold C. Hutchison ([email protected])