The Iris-class ships were designed as dispatch vessels and were later redesignated as second-class protected cruisers.

They displaced 3,730 long tons (3,790 t) at normal load[1] and were the first British warships with an all-steel hull.

[1] The engines were designed to produce a total of 6,000 indicated horsepower (4,500 kW) for a speed of 17 knots (31 km/h; 20 mph).

[3] The ship carried enough coal to steam 4,400 nautical miles (8,100 km; 5,100 mi) at 10 knots (19 km/h; 12 mph).

[1] The Iris-class ships were originally armed with ten 64-pounder (6.3-inch (160 mm)) rifled muzzle-loading (RML) guns, eight on the main deck and the remaining pair on the upper deck on pivot mounts to serve as chase guns fore and aft.