The frigate's battery combined two single 4-inch guns, a changing light anti-aircraft fit, a Hedgehog anti-submarine mortar, and roughly fifty depth charges. This mix could engage surfaced or submerged submarines, aircraft, and light surface craft while protecting a convoy. Wartime light-AA lists deserve caution because crews often added weapons when mounts and ammunition became available. Groups of frigates could also bluff heavier opponents by forming up and firing like destroyers. Fighting major surface combatants was outside their intended role.
Chapter · 45:56-49:44
Diamantina's convoy-defense weapons fit
Diamantina's 4-inch guns, light anti-aircraft weapons, Hedgehog mortar, and depth charges were balanced for convoy defense rather than fighting major surface combatants.