Choosing secondary guns for aircraft or surface threats

Were 5.9-inch secondary guns worthwhile, or would more 4.1-inch guns have been better?

It depends on the theater: more 4.1-inch guns suit air-heavy combat, while a mixed battery can make sense when surface threats remain important.

The value of a heavy 5.9-inch secondary battery depends on the expected theater. A Pacific campaign dominated by aircraft rewards more 4.1-inch anti-aircraft weapons. Mediterranean operations, where surface threats remain important alongside air attack, favor a mixture of calibers. Armament choices must follow the expected threat environment instead of a universal design rule.