Here are two photos of railway-based Flak I came across during the research for my new book "Kraftwagen-Flak":
Are these both Naval mountings? The bottom image looks like a flak version of the 10.5cm submarine gun.
Navweaps says there was an 10.5cm L/45 flak gun used on German capital ships. There was an older 10.5cm L/40 flak gun
but I haven't found any images of that one.
Charlie