Oldest of the gun cruisers in Commonwealth service, the Chatham class remained in service due to the eternal shortage of cruisers suffered by the Commonwealth nations. For their roles as Escort Cruisers, they did not need high speed, lots of guns, what they did need was to be there. Each of the older cruisers of the Chatham, Birmingham, Chester, Arethusa classes at sea doing patrol duties meant that one less front line cruiser was required to undertake the same duties. The ships were well armed enough to be able to take on the German/Italian/Japanese armed merchant raiders and sink them. If they were being used as convoy escorts, the ships would normally house the Escort Commander, and given an asdic set and a few depth charges they could also attack U-Boats.
Some of the most modern cruisers available on the outbreak of WW1, they quickly were reduced in duties as the 'C' class cruisers were completed and entered service. From 1920 the class was quickly spread out to the Commonwealth Nations. Chatham went to New Zealand, Dublin and Dundee went to Southern Africa, while Australis retained its four Chatham class.
Service during the 1920's saw the class slowly being reduced in power and prestige, the mid-ships 6" was replaced by a pair of 4" AA guns. The number of ships boats was reduced. The ships lost their tall top masts as wireless transmitting technology improved. The crunch for the ships came in the mid 1930's, they were obsolete, but still had value in the roles suggested in the opening paragraph. Some work would need to be done to the ships to make them more suitable for their roles and make them look slightly more modern. Many minor refits over the years had already modified the ships considerably. The submerged torpedo tubes were removed, the coal fired boilers converted to oil firing which increased the power of the engines and the speed from 25 to 26 knots. the aft pair of 6" were removed and replaced with a superfiring 6" mounting aft and a pair of 21" torpedo tubes either side.
The new funnels and bridge meant that the pair of 6" beside the bridge were removed leaving the ships with an armament of only three 6" which was considered enough to take care of the armed merchantmen they would spend most of their time hunting for. If they came across anything bigger they could scream for help and run.
Chatham class cruiser in dockyard hands ready to be rebuilt.
