In my previous posts about Corsair, I mentioned that I have to expand my first draft to make it a proper book-sized book. Doing that revealed a structural problem. The original short story "The Barbary Shore" had extensive flashback sections, since it was simultaneously about Captain Santiago of Orbital Command battling Captain Black the Space Pirate and about the failed romance years earlier between Elizabeth Santiago and David Schwartz at M.I.T.
The structural problem was that while the short story divided neatly into the main action and the flashbacks, the novel didn't. There's a lot more stuff going on in the "present time" of the novel, while the amount of "back then" flashback material remains about the same. As a result, I had a story with a handful of flashback scenes scattered through the first few chapters, then no more. That felt clumsy.
So I decided on major surgery. I bundled all the flashback sections into a single chapter. So now the book's first chapter takes place "last year" when Elizabeth and David slug it out in space, then there's a chapter taking place "long ago" when they had their failed romance, and then the rest of the book is a straightforward chronological narrative.
I think the new organization will let me get away with using narrative scene-setting to tell when things are happening, until the actual launch of the pirate spaceship -- at which point I can put a little "mission clock" header at the start of each scene to make it clear that things are happening very fast for the rest of the book.