It can go either way. Of course it's pretty much mandatory for named ships the first time used in a document. After that it can be used or not. For numbered ships I've also seen it used and not used, and there doesn't seem to be a standard. USS PT-138 may be officially okay, but it looks weird in print, so depending on how official the paper is it might not matter.
__________________
“Never do anything you can't take back.”
—Rocky Russo
|