|Preceded by:||Edgar class|
|Succeeded by:||Diadem class|
|Displacement:||14,200 long tons (14,400 t) (deep load)|
|Length:||500 ft (152.4 m) (p/p)
538 ft (164.0 m) (o/a)
|Beam:||71 ft (21.6 m)|
|Draught:||27 ft (8.2 m)|
|Installed power:||25,000 shp (18,600 kW)|
2 vertical triple-expansion steam engines
48 Belleville water-tube boilers
|Speed:||22 knots (40.7 km/h; 25.3 mph)|
|Range:||7,000 nmi (12,960 km; 8,060 mi) at 14 knots (25.9 km/h; 16.1 mph)|
|Armament:||2 × BL 9.2-inch (234 mm) Mk VIII guns
12 × QF 6-inch (152 mm) guns
16 × 12-pdr (3-inch, 76 mm) guns
12 × 3-pdr (47 mm) guns
4 submerged torpedo tubes
|Armour:||Deck: 2–6 in (51–152 mm)
Barbettes: 6 in (152 mm)
They were designed for hunting down commerce raiders such as the Russian armoured cruiser Rurik and numerous French armoured cruisers of the era. As a result, these were very large cruisers intended to be able to dominate other cruisers in a one-on-one battle. A secondary function was to act as a high speed, long range transport (which in fact was their only actual use during war).
The original armament was to be a uniform battery of twenty 6 inch guns. However, the Director of Naval Ordnance strongly believed that fewer larger (8 inch) guns would produce a better ship. The Office of Naval Construction countered that a 6 inch gun was suitable for fighting other cruisers, and that the 8 inch gun was too slow-firing to fight cruisers yet too small to fight battleships. He asked for at least a few guns of at least 9.2 inches as the smallest capable of damaging a contemporary battleship. This argument won, and the armament as constructed became two 9.2 inch guns and twelve 6 inch guns. Observers criticized these ships for their apparently light armament given their size. However they had excellent sea keeping, high speed, and long range, all of which required space and tonnage.
These were the first cruisers in the Royal Navy with four funnels.
These ships had an armoured deck to stop plunging shells. This deck curved, with its crown in the middle of the ship 3 feet 6 inches (1.07 m) above the waterline, and the edges were 6 feet 6 inches (1.98 m) below the waterline. The deck was 6 inches (150 mm) thick over the machinery, 4 inches (100 mm) thick over the magazines, and 2.5 inches (64 mm) thick in the middle of the ship.
The dimensions of this class were limited by the then available dockyards available to build and maintain them.
In comparison to the Edgar class, these ships had a crew 64% larger, cost 61% more to build, had more than twice the horsepower, had 660 tons of armour versus 340 tons, were two knots faster, but had very nearly the same armament. The Edgar class remained to fight during the First World War, but the Powerful class had left the active fleet by then.
The following table gives the build details and purchase cost of the members of the Powerful class. Standard British practice at that time was for these costs to exclude armament and stores.
|Ship||Builder||Date of||Cost according to|
|Laid Down||Launch||Completion||(BNA 1904)||(BNA 1906)|
|Powerful||Vickers, Barrow in Furness||1894||24 July 1895||8 June 1897||£741,870||£705,335|
|Terrible||J&G Thompson, Clydebank||1894||27 May 1895||24 March 1898||£740,584||£708,619|
|Ship||Date||4 hours forced draught||30 hours natural draught||Source|
|Powerful||1896||25,866 ihp||21.8 kn (40.4 km/h)
|18,433 ihp||20.6 kn (38.2 km/h)||Janes 1900|
|Terrible||1897||25,572 ihp||22.4 kn (41.5 km/h)||18,493 ihp||20.96 kn (38.82 km/h)||Janes 1900|
Terrible 1898 Trials
- 60 hours at 1/5 power (20 boilers) 5084 ihp = 12.8 kn (23.7 km/h)
- 68 hours at 2/5 power 10,246 ihp = 17 kn (31 km/h)
- 60 hours at 3/5 power 15,554 ihp = 19.6 kn (36.3 km/h)
- 60 hours at 3/4 power 18,515 ihp = 20.3 kn (37.6 km/h)
- 8 hours (22,000 ihp nominal) = 23,053 ihp = 20.7 kn (38.3 km/h)
- 4 hours at full power = 25,513 ihp = 21.9 kn (40.6 km/h)
Both ships served in the China Station and provided landing parties which fought in the relief of the Siege of Ladysmith in the Second Boer War in South Africa. This event inspired the Field gun competition. Crews from the two ships also took part in suppressing the Boxer Rebellion in China. After 1904 they were laid up as an economy measure. During the First World War, they had most of their armament removed and served as troop transports and later accommodation ships.
- Jane 1900, p. 108.
- Preston 2002, p. 45.
- As with the Diadems that followed them Brassey's Naval Annual (BNA) gave costs for these ships that were on average £34,000 greater in the 1904 edition than in the 1906 and subsequent editions.
- Brassey's Naval Annual 1904, p220-233
- Brassey's Naval Annual 1906, p216-223
- Gardiner, Robert, ed. (1979). Conway's All the World's Fighting Ships 1860–1905. Greenwich: Conway Maritime Press. ISBN 0-8317-0302-4.
- Preston, Antony (2002). The World's Worst Warships. London: Conway Maritime Press. ISBN 0-85177-754-6.
- Jane, Fred T., ed. (1900). Jane's Fighting Ships 1900. Marston.
- Brassey's Naval Annual 1904
- Brassey's Naval Annual 1906
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