Why displacement alone does not define a heavy cruiser

HMS Belfast demonstrates why a 10,000-ton cruiser was not automatically heavy: she remained a light cruiser because of her twelve 6-inch guns, protection scheme, and assigned duties. Hawkins carried 7.5-inch guns because 6-inch weapons were considered too light for hunting converted German merchant raiders. The Royal Navy also studied 9.2-inch guns, but the hull could not carry enough of them for the desired role. Torpedoes supplied a threat against anything larger that appeared. A treaty ceiling later became mistaken for a complete warship category even though gun calibre, armour, and mission all mattered.