In the Solar Cycle, by Gene Wolfe, is it possible that the Worldship, the Whorl, used as locale of The Book of the Long Sun is also the universe hopping ship that Severian uses as a transport to undergo his trial?
I think it is possible, however they are being represented at different periods in time. There are references to there only really being one Ship that's used to transport people to Yesod, and that there are only different versions of that same ship as it's seen at various points in time that are relative from both perspectives.
From the book:
These ships that sail between the suns are not like the ships of Urth.
Later, we see a man named Purn say:
"The name of his ship? No, I don't think he ever mentioned it. Wait... He said he'd been on several. 'Long I signed on the silver-sailed ships, the hundredmasted whose masts reached out to touch the stars."' "Ah." Purn nodded. "Some say there's only one. That's something I wonder about, sometimes."
"...Only this ship here and the other ones like it, allowing that there's more than the one..."
Is this our clue that they are the same ship? Severian could be intending to imply that only ships like the one he was on, "these ships", were "ships that sail between the suns", then later Purn suggests that there is only one of "these ships" that "sail between the suns". Combine that with the knowledge that the Whorl behaves at the end of Long Sun in a very similar way to the universe hopping ship by stopping long enough to unload and load cargo then moving on to an unknown destination, and the Whorl travelled between suns, it follows that the Whorl was the original starship and that it became the giant ship we see now, only we see it as the universe-ship later relative to it's own time-stream.
I know there is more supporting evidence that there is only one star-ship like the one Severian is aboard all over the story so, really all that's left is to determine if the Whorl was like that ship. I think that it was, and that it is the only ship capable of interstellar flight.