[tanknetter]

I read someplace that the SSN-23 (jimma carter) is the only Navy boat known by it’s sail number and has no nickname.

Probably relates, in an informal manner, more to the nature of SSN-23's mission and capabilities. She's the most highly-classified "known" ship in USN service (I'm not discounting the probability that there are other more highly-classified black-world ships, like successors to the SeaShadow, in existence).

At one point she, like her predecessor USS Parche, was the only "attack" boat based at an SSBN homeport (the Trident facility in Washington State). She was joined there a few years back by her two half-sisters (Seawolf and Connecticut) to tighten up and streamline the logistics around the 3-ship class.

[alpo]

It has no nickname because the sailors aboard will not utter the name of the traitor it is named after.