Distinguishing 8-inch and 16-inch shell splashes

How different must shell sizes be for observers to distinguish their splashes, and could 8-inch and 16-inch fire be told apart?

Yes. Eight- and sixteen-inch shells differ enough for their splashes to be distinguished at practical ranges, although a detonation is easier to identify than water impact alone.

An 8-inch splash can be distinguished from a 16-inch splash at practical battle ranges because the size difference is substantial. A shell entering the water without exploding gives less information than a detonation. The discussion then considers what happens below the surface, where water pressure can affect a fuze or crush the shell. Whether a particular shell detonates before reaching crush depth remains disputed.