All Imperial Navy vessel names are prefixed CS (for “Coronal’s Ship”), having the privilege of a prefix without an inserted service name. The vessels of other services utilize infixes to distinguish themselves: vessels operated by the non-military instrumentalities of the Imperial Service (primarily the Exploratory Service, but also diplomatic vessels, postal packets, empire ships, and the like) are designated CSS (“Coronal’s Service Ship”). Merchantmen and other commercial starships are designated CMS (“Coronal’s Merchant Ship”), and privately owned non-commercial starships simply IS (“Imperial Ship”).
My house style, insofar as I have one, is to omit the article before the name on the grounds that it’s a name , belike, and I don’t go around calling myself the Alistair except on special occasions.
(Finger-macro runaways aside, the prefix shouldn’t be emphasized either, but finger-macro runaways are common enough that my lovely editor has to fix that one a lot.)
As a former Sailor in the USN, we used both. And we typically dropped the USS from the ship names in conversation. “On the Georgia, we do X this way” and “I served on Georgia, Kentucky, and Squadron 19.” (with the caveat that Georgia BN or GN usually got specified, as Georgia got a significant refit and change in mission about 20 years ago, to give an idea of when you were there)