HMS Iris the lead ship of her class of two ships built for the Royal Navy in the 1870s. They were the first all-steel warships to serve with the Royal Navy.
The Iris-class ships were designed as dispatch vessels and were later redesignated as second-class protected cruisers. Iris had an overall length of , a beam of , and a draught of . They displaced at normal load and were the first British warships with an all-steel hull. Their crew consisted of 275 officers and ratings.
The Iris class was powered by a pair of horizontal four-cylinder Maudslay, Sons and Field compound-expansion steam engines, each driving one propeller shaft using steam from eight oval and four cylindrical boilers. The engines were designed to produce a total of for a speed of . Iris initially reached a maximum speed of from during her sea trials, but after new propellers were fitted, achieved from . The ship carried enough coal to steam at . She was initially fitted with a barque sailing rig, but this was removed after a few years.
The Iris-class ships were originally armed with ten 64-pounder () 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.
Iris was laid down at the Pembroke Dockyard on 10 November 1875, launched on 12 April 1877 and completed in April 1879. She served with the Mediterranean Fleet from 1879 to 1887, then in the Portsmouth Reserve from 1887 to 1903. She was a tender to in 1903â 1904 and was sold for scrap on 11 July 1905.