I drove myself crazy this morning trying to remember a phrase I'd once heard for a useless officer aboard ship (insert joke from all NCO's here). All my naval dictionaries and sources produced nothing except a lot of rude phrases not suited to the scene I was writing.
Finally, after lunch, the penny dropped and I remembered I'd heard it used in an episode of Star Trek, the original series where Kirk gets replaced by a computer ("The Ultimate Computer". Thank you, Wikipedia). So I typed the search question and got back "Captain Dunsel, meaning 'doesn't sail'."
Cool! But knowing better than to trust internet research on its own, I dug a little deeper and found this may have been a phrase invented for Starfleet Academy types, and not a real, historical phrase for a useless officer.
So, I'm back to revising the scene so I'm not inserting a phrase that's not only anachronistic, but fake. By the way, back in the day I would have posted the question in writing to a science fiction APA (amateur press alliance) publication because before there was an internet, we used to say "All knowledge is contained in fandom". I would have gotten an answer, but it might have taken a few weeks...or months.
Now with the internet I have new ways to waste time, but at least I may find my mistakes more quickly.