HMAS Christchurch (CA-1942+)
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Biggest of the Commonwealth cruisers, these ships benefitted from the relaxation of the Washington Treaty limits. With a standard displacement of 15,000 tons the ships were 50% bigger than the original County class of 15 years previous. With 12 semi-automatic 7.5" 50 caliber main battery, one of the major reasons for the large increase of size is the much larger magazines required for the faster firing guns. The big spacious turrets have remained the same through all of the Heavy Cruiser types from 1925. In this class they have had to be spaced out a bit further to allow for the larger magazines. The 7.5" guns fired at normally 5-6 rounds a minute while Christchurch's new breech and block (based and updated from the French system patented in 1930 and used for the 5.1" on Strasbourg and Le Hardi types) could fire up to 10 rounds a minute. The French system had many teething troubles as did the Australis system. These problems had theitr final solution in August 1942. Applying the technology to more gun systems would have to wait till after the war was won.
The two ships of this class were laid down in 1938 and 1939, HMAS Christchurch being completed in June of 1942, and HMAS Launceston was completed in November 1942. The Australis Navy would have liked to have built more but the cost of the ships were as expensive as the battlecruiser New Zealand and they could build 3-4 conventional 6" cruisers for the price of one of these ships.
|Displacement||15,000 tons std, 19,250 tons full load|
|Machinery||4 shaft Steam turbines, 100,000shp|
|Range||8,500 miles at 18 knots|
|Armour||4.5" side, 3" deck, 3" turrets.|
|Armament||12 x 7.5" (4x3)
12 x 4.5" (6x2)
32 x 40mm (6x4 4x2)
It was the triple turret and guns that caused the longest delay to these ships and at one stage they were going to be fitted with the earlier mark just to get the ships to sea. A breakthrough for the problem was made and the ships were completed only 3 months late. It was just as well the turrets were a generous size as can be seen from the amount of equipment that was fitted in. Below is a medium triple turret layout for semi- automatic weapons. (This is an actual semi-automatic turret from the Des Moisne class which requires a larger ship than Christchurch the US ships generally carrying more rounds per gun than their European counterparts - 8" guns -v- 7.5"guns, 8" fires 250+lb shells, 7.5" 200lb shells).
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