I keep forgetting about the prototype systems I create with spacemaster when I make a ship design, a few times I've refit a shipyard to the unmodified version, thigh it can be fixed easily enough with spacemaster mode, there was a few times when I wondered why the ship taking so long to buikd( I created the production engines in planetary factories, of course the ship didn't use them) or I couldn't create multiple classes from the yard as I had hoped (half the designs used either engine).