Iris-class cruiser
| Class overview | |
|---|---|
| Name | Iris class | 
| Builders | Pembroke Dockyard, Wales | 
| Operators | Royal Navy | 
| Succeeded by | Leander class | 
| Built | 1875–1879 | 
| In commission | 1877–1914 | 
| Completed | 2 | 
| Scrapped | 2 | 
| General characteristics (as built) | |
| Type | Despatch ship (later protected cruiser) | 
| Displacement | 3,730 long tons (3,790 t) | 
| Length | 315 ft (96 m) or 331 ft 6 in (101 m) | 
| Beam | 46 ft (14 m) | 
| Draught | 20 ft 6 in (6.2 m) | 
| Installed power | 12 boilers; 6,000 ihp (4,500 kW) | 
| Propulsion | 2 × shafts; 2 × compound-expansion steam engines | 
| Sail plan | Barque-rigged | 
| Speed | 17 knots (31 km/h; 20 mph) | 
| Range | 4,400–4,950 nmi (8,150–9,170 km; 5,060–5,700 mi) at 10 knots (19 km/h; 12 mph) | 
| Complement | 275 | 
| Armament | 10 × 64 pdr rifled muzzle-loading (RML) guns | 
The Iris class consisted of two ships, HMS Iris and HMS Mercury, built for the Royal Navy in the 1870s. They were the first British all-steel warships.