After the beginning of World War I in August 1914, Swiftsure escorted troop convoys in the Indian Ocean until she was transferred to the Suez Canal Patrol in December.

[1] Swiftsure was assigned to convoy escort duties in the Atlantic from early 1916 until she was paid off in April 1917 to provide crews for anti-submarine vessels.

Sir Edward Reed, chief designer for Armstrong Whitworth, was in Chile for health reasons at the time, and met with Chilean Navy officials to discuss the idea of purchasing or building two battleships with high speed and a powerful armament on a low displacement.

[2] The ships were considered second-class battleships, lightly constructed, armed, and armoured by British standards; Swiftsure, in fact, suffered from structural weakness while in service and required hull strengthening, although Triumph did not have such problems.

Both were completed in June 1904 and entered service with the Royal Navy, Constitución as Swiftsure and Libertad as HMS Triumph.

The ships were some 375 long tons (381 t) overweight compared to their designed displacement which increased their draught and reduced their freeboard.

[1] The ships were powered by two four-cylinder inverted vertical triple-expansion steam engines, each driving a single propeller.

A dozen Yarrow boilers provided steam to the engines at a working pressure of 280 psi (1,931 kPa; 20 kgf/cm2).

The engines produced a total of 12,500 indicated horsepower (9,300 kW) which was intended to allow the ships to reach a speed of 19.5 knots (36.1 km/h; 22.4 mph).

The engines proved to be more powerful than anticipated and both ships exceeded 20 knots (37 km/h; 23 mph) during sea trials.

This made them the fastest battleships in the Royal Navy at the time of their completion, although their sustained speed in service was slightly slower than that of the older Duncan class.

[12] They carried a maximum of 2,048 long tons (2,081 t) of coal, enough to steam 6,210 nautical miles (11,500 km; 7,150 mi) at 10 knots (19 km/h; 12 mph).

[4] In service they proved to be more economical than first thought with an estimated range of 12,000 nautical miles (22,000 km; 14,000 mi) at 10 knots.

They followed the standard British practice of the time of mounting the main battery in two twin turrets, one forward and one aft.

[16] A more serious problem was that they were mounted low in the ship—only about 10 feet (3 m) above water at deep load—and were unusable at high speed or in heavy weather as they dipped their muzzles in the sea when rolling more than 14°.

The waterline main belt was composed of Krupp cemented armour (KCA) 7 inches (178 mm) thick.

Swiftsure was briefly placed in reserve from 7 October 1908 to 6 April 1909 when she was recommissioned for service with the Mediterranean Fleet.

From 27 January to 4 February 1915, the ship helped to defend the Canal during the First Suez Offensive by Ottoman forces.

On 11 April 1917, the ship arrived at Chatham where she was paid off and placed in reserve to provide crews for anti-submarine vessels.

Later that year, the ship was disarmed and stripped in order to be used as a blockship during a proposed second raid on Ostend.

Triumph received a brief refit at Chatham Dockyard in October 1908 and was transferred to the Mediterranean Fleet on 26 April 1909.

She was torpedoed and sunk off Gaba Tepe by the German submarine U-21 while bombarding Ottoman fortifications in the Dardanelles on 25 May 1915.