From carrier gun batteries to layered task forces

Why did early carriers mount cruiser-sized guns, and what replaced that idea?

Heavy guns offered self-defense when carrier roles were uncertain, but exercises showed that layered cruiser and destroyer escorts were more effective.

Heavy guns on early carriers reflected uncertainty about whether cruisers would always be available for protection. The 1929 exercises helped establish that carriers required dedicated cruisers and destroyers. By the mid-1930s, the Royal Navy was developing a recognizably modern task group in which different escorts covered different threat ranges.