The Powerful class were a pair of first-class protected cruisers built for the Royal Navy (RN) in the 1890s, designed to hunt down enemy commerce raiders.

Powerful served as the flagship of the Australia Station in 1905–1912; shortly after her return home, she became a training ship and remained in that role until she was sold for scrap in 1929.

The impetus for the construction of the Powerful class began with the laying down the Russian armoured cruiser Rurik in 1890 that was intended to be used as a commerce raider, although the Admiralty was fully occupied with the extensive naval construction mandated by the Naval Defence Act 1889 and could do nothing in response at that time.

Some preliminary discussions occurred in November 1891, but it was not until the following year that William White, the Director of Naval Construction, was told to prepare sketch designs for a ship more heavily armed, at least as well armoured, faster and with greater endurance than Rurik and her successors.

White believed that the design required lightweight, efficient Belleville water-tube boilers if it was to achieve its requirements, but conservatives in Parliament and the Admiralty resisted the idea, given the RN's failures with water-tube boilers in the past, until extensive trials were conducted by the torpedo gunboat Sharpshooter and proved to be a complete success.

Naval historian Antony Preston commented: "The Powerful and Terrible also mark the extreme folly of building cruisers to match specific opponents.

[9] Their engines were designed to produce a total of 25,000 indicated horsepower (19,000 kW) using forced draught[10] for a maximum speed of 22 knots (41 km/h; 25 mph).

[6] The mounts could elevate up to +15° and the guns fired a 380-pound (170 kg) projectile with a muzzle velocity of 2,329 ft/s (710 m/s) to a maximum range of 12,846 yards (11,746 m).

[11] Their secondary armament of a dozen 40-calibre quick-firing (QF) 6-inch (152 mm) Mk I or II guns was arranged in casemates amidships.

[15] The ships were equipped with a dozen 3-pounder (47 mm (1.9 in)) Hotchkiss guns mounted in the pair of fighting tops on the military fore and mainmasts.

The ships were refitted in 1902–1903 and four more six-inch guns were added in casemates amidships at that time, although no additional ammunition could be accommodated.

She set a record ferrying relief crews for the Mediterranean Fleet from Portsmouth to Malta in only 121 hours in late 1898.

The ship was ordered to relieve Powerful in the Far East in late 1899, but they were both diverted to South Africa in light of rising tensions between the British and the Boers.

Terrible's captain, Percy Scott, then improvised field carriages for some naval guns to satisfy a request for more long-range artillery.

Hedworth Lambton led a naval brigade and some of Percy's guns to reinforce the garrison of Ladysmith in late November.

[22] The ships continued on their respective voyages after Ladysmith was succored in March, Powerful to much acclaim in England and Terrible to China where her crew and guns helped to suppress the Boxer Rebellion a few months later.