The second destroyer model appears to carry three twin 4.7-inch mountings and a twin 4-inch mounting. The mounting count is uncertain, but the guns' different roles are clear. The 4-inch guns provide anti-aircraft protection when aircraft get close. The 4.7-inch battery supplies the principal firepower against destroyers and other ships.
Notable Point · 0:59-1:27
Mixed gun batteries divide surface and air-defence roles
A second destroyer model pairs 4.7-inch guns for surface combat with 4-inch guns for anti-aircraft defence.