[quote=@Willy Vereb]This is a common issue so excuse me for using you as a device but I say it now.
The setting is more like 1950s retro sci-fi. You aren't hard limited by equipment from the 50s. You can have spider legged walker tanks and other weird vehicles all you want.[/quote]

Excellent point; though, aesthetics and maybe history aside, my question is broadly the same - what is considered excessively powerful? While I'm not a warfare buff and don't know names of things, it's very much inspired by the monstrosity that Germany was trying to build that was considered technically stupid and impractical in the sense that nobody really knows how useful it would actually be. What I'm kinda hoping for is something that could legitimately scare off a ship that got too close - provided it works. But, as I ask - is that OP?

Zeppelins, if I choose that line, would be contemporary inventions. Only the tank (which for all intents and purposes is one big-ass stationary cannon) would be pre-Cataclysmic.