Poated earlier:1a: Rank is based on reknown. When you buy something keep this in mind for if you drop below the required reknown for that rank you will be demoted.
This seems like a terrible design in the game
.
BDU: "Lets see, you're a well known captain and you've sank lots of ships, but since you want to upgrade your sub im afraid were going to have to demote you."
You: "WTF"