Shrug, as I've said before, I never came up with a proper scale when I designed the ships, just went with whatever was pretty. Though, in my mind I don't see destroyers as 150-175m but that's probably because that'd be the size of the modern wet navy ships (with the current trend of aircraft carriers and destroyers) and my service in the Navy.
Oh they are definitely multi-person crewed ships. The blue circle is technically the ship's bridge.
From this thread: