OK, I'm making some progress, but I still have problems.
I've found the flag cfg entry in the .dat of the parent ship and located the last entry with a float value of 3.1415925. I think it's DA0F 4940. But when I open up the Lake Ship's .dat and locate the same entry, the float value isn't 0 - it's correctly listed as 3.1415925. Pasting the same entry over that one does nothing to the upside down flag.
I don't understand why the float value is listed correctly when the error is supposed to be that the value is 0.

Am I looking at the wrong entry - it doesn't seem likely though.
(BTW - Completely unrelated but before I began any of this process, one of the ship's deck crates disappeared. That's one less I have to worry about. I haven't tried to get rid of the other yet.)
Here is a screenshot of the value in Hex Workshop that I am talking about.