Have the russian circular ships been mentioned yet?
https://www.youtube.com/watch?v=R5AUGq4Voeg
During the flurry of ship building in the late 1800's, Russia built two battleships that were nearly circular, figuring on maximizing the area per perimeter (and thus armor thickness). The two ships were untested in battle, with some controvesy as to how effective they would have been in battle. They certainly weren't good at maneuver, but they weren't supposed to be. They severed for over 25 years.
Next time you need a wacky steam-punk vehicle, remember Russia's perfectly round ships. With six propellers. And a single turret in the exact center. Just look at the picture:
https://en.wikipedia.org/wiki/Russia...ale_model).jpg