HMS Cyclops was the leading vessel of the Cyclops-class breastwork monitors constructed for the Royal Navy in the 1870s. Laid down on 10 September 1870 by Thames Ironworks in London and launched on 18 July 1871, she was commissioned in January 1872. The ship measured approximately 225 feet (68.6 meters) in length between perpendiculars, with a beam of 45 feet (13.7 meters), and a deep load draught of 16 feet 3 inches (4.95 meters). She displaced around 3,480 long tons (3,540 metric tons) and had a crew complement of 156 officers and men, later increased to about 191 following refits. HMS Cyclops was powered by two 4-cylinder inverted compound steam engines, each driving a single propeller shaft, which together produced 1,528 indicated horsepower during trials, reaching a top speed of approximately 10.79 knots. She carried 250 long tons of coal, enabling her to steam up to 3,000 nautical miles at 10 knots. Her armament comprised four 10-inch rifled muzzle-loading guns housed in twin-gun turrets fore and aft, capable of firing solid shot and explosive shells, with hydraulic jacks for elevation. The ship's armor was notable for its extensive breastwork, with an 8–9 inch (203–229 mm) wrought iron waterline belt amidships, tapering to 6 inches at the ends. The superstructure and conning tower were fully armored with 8–9 inches of wrought iron, while the gun turrets had 10-inch faces and 9-inch sides and rears. All vertical armor was backed by 9–11 inches of teak, and her decks were 1.5 inches thick. Construction delays extended her fitting-out period until 4 May 1877, with a total cost of £156,782. An 1880s refit improved stability and habitability by extending the superstructure, strengthening the breastwork, adding watertight bulkheads, and fitting additional armament, including quick-firing Hotchkiss guns and machine guns for torpedo boat defense. HMS Cyclops saw limited active service, primarily during the brief four-month deployment in Portland Harbour during the Russo-Turkish War of 1878, before being placed in reserve. She participated in fleet maneuvers in the late 19th century and was finally sold for scrap in 1903, marking the end of her maritime significance as a coastal defense vessel of her era.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.