A total of eight scout cruisers were ordered, two each from Armstrong Whitworth, Fairfield, Cammell Laird and Vickers. Cammell Laird's ships, the , were long overall and between perpendiculars, with a beam of and a draught of . Displacement was normal and deep load. Twelve Normand water-tube boilers fed steam to two 4-cylinder triple-expansion steam engines rated at and driving two shafts. was achieved using forced draft during sea trials, allowing a trial speed of . Range was at . A thick armour belt protected the ship's engine rooms, with a armoured deck over the ships engines and an armoured deck of elsewhere, while the ship's conning tower was protected with of armour.