So... somehow I bugged the game out so one of my custom-built ships now upgrades into the Hero-class ships. They're twice as powerful as a regular ship and take up no Command Points.

No, really.

The closest thing I can think of is that somehow, customizing/upgrading one of my Hero Ships caused this to happen. I've included the save file so people can check it out for themselves; there's a flotilla of Barques in Botha you can upgrade to the Hero Ships.

Save file: Upgraded to Hero Ship.zip

Could a dev/mod please move this to the Tech Support forum? Or flag it as a bug? Infinitely-stacking fleets of Hero Ships is... gamebreaking.

Did it erase all your custom ship designs as well? Because I think I know what you did if it does.