Battle-class destroyers needed to carry heavy 4.5-inch between-deck mounts alongside much stronger light anti-aircraft armament. Concentrating the main mounts forward kept their weight and internal space demands away from the machinery. It also preserved room for torpedo launchers, depth charges or Squid, and a substantial 40 mm battery. The early fit described here includes four twin radar-directed 40 mm mounts and four to six single 40 mm guns. Eight 21-inch torpedoes supply the principal attack against large surface ships, while the 4.5-inch guns engage lighter targets. An extra aft main mount would consume weight and space considered more useful for air defence.
Chapter · 2:00:16-2:04:58
Why Battle-class destroyers put their main guns forward
The Battle class concentrated heavy 4.5-inch mounts forward to make room for torpedoes, anti-submarine weapons, and increasingly important anti-aircraft systems.