I am not a teacher.
Number 2 is somewhat unnatural. I would like to see a comma or two in there: "USS Skipjack (SSN 585), attack submarine, on sea trials". That looks like a caption, and captions have a style all their own, partly because they have to be short. Don't look to captions for usage.
"The Lenin nuclear icebreaker" is impossible. You could have "the Lenin, a nuclear icebreaker", but look for "the nuclear icebreaker Lenin". Icebreakers are ships like any other. We italicize ship names.