Heavy Cruiser

The heavy cruiser was a type of cruiser, a naval warship designed for long range and high speed, armed generally with naval guns of roughly 203mm calibre (8 inches in caliber) and displacing approximately 10,000 tons. While the general mission of the heavy cruiser to act as a fast scout for a battle fleet and protect and hunt down commerce was largely unchanged from the days of sail, its design parameters were dictated by the Washington Naval Treaty of 1922 and the London Naval Treaty of 1930.

The heavy cruiser can be seen as a lineage of ship design from 1915 until 1945, although the term 'heavy cruiser' only came into formal use in 1930. The heavy cruiser's immediate precursors were the light cruiser designs of the 1900s and 1910s, rather than the armoured cruisers of before 1905. When the armoured cruiser was supplanted by the battlecruiser, an intermediate ship type between this and the light cruiser was found to be needed—one larger and more powerful than the light cruisers of a potential enemy but not as large and expensive as the battlecruiser so as to be built in sufficient numbers to protect merchant ships and serve in a number of combat theaters.