Displacement was 5,250 long tons (5,330 t) normal and 5,800 long tons (5,900 t) full load.Machinery was similar to the Bristol class, with again a single example (Yarmouth) having the Brown-Curtis turbines and two-shaft arrangement used in Bristol, while the remaining three ships had the four-shaft, Yarrow turbine machinery. while the main gun armament was changed to eight BL 6 inch Mk XI guns.While main armament again consisted of eight 6 in guns in single mountings, a new gun, the BL 6 inch Mk XII was used.
While the earlier ships were protected cruisers, depending on an armoured deck deep within the ship to protect machinery and magazines, the Chathams relied on a vertical belt of armour.
The Chatham class were 458 feet (139.6 m) long overall, with a beam of 49 feet (14.9 m) and a draught of 16 feet (4.9 m).
One ship, Bristol, had Brown-Curtis turbines driving two propeller shafts, while the remaining three ships used Parsons turbines driving four shafts.
The Bristols were protected cruisers, with an armoured deck providing protection for the ships' vitals.
The five British-built ships commissioned between 19, while Brisbane, the Australian-built ship was laid down in 1913 and completed in 1916.
The major difference between the Chathams and the earlier Towns was a revised armour scheme.The First World War caused the construction of Adelaide, which was reliant on materials and parts from the United Kingdom, to be heavily delayed, with Adelaide not completing until 1922.They were closely based on the Chatham class but with a revised armament.One problem with the armour of the Bristols which was shared with the other Town-class ships was the sizable gap between the bottom of the gun shields and the deck, which allowed shell splinters to pass through the gap, giving large numbers of leg injuries in the ships' gun crews.It was originally intended that the Bristol class would be fitted with a main gun armament of unshielded 4-inch (102 mm) guns, but the need to counter German light cruisers (such as the Königsberg class), which were armed with ten 105-millimetre (4.1 in) guns that outranged British 4-inch guns, resulted in the new class's armament being revised.The Town class was a group of twenty-one light cruisers built for the Royal Navy (RN) and Royal Australian Navy (RAN).