HMS Iron Duke was the last of four Audacious-class central battery ironclads constructed for the Royal Navy, launched in 1870 and completed in 1871. She measured 280 feet (85.3 meters) in length between perpendiculars, with a beam of 54 feet (16.5 meters) and a draught of approximately 21 feet 7 inches (6.6 meters) forward and 22 feet 7 inches (6.9 meters) aft. Displacing around 6,034 long tons (6,131 metric tons), she had a tonnage of 3,774 tons burthen and a crew complement of about 450 officers and ratings. The vessel was powered by two horizontal-return, two-cylinder steam engines, each driving a single 16.6-foot (5.03-meter) propeller, and six rectangular boilers. During sea trials in November 1870, Iron Duke achieved a speed of 13.64 knots (25.2 km/h), with a designed speed of 13 knots. Her armament included ten 9-inch (229 mm) rifled muzzle-loading guns, with six on the main deck and four mounted on the upper deck battery, as well as four 6-inch (152 mm) chase guns and six smaller 20-pounder breech-loading guns added later. In 1878, she was fitted with four 14-inch torpedo launchers, and in the mid-1880s, her 6-inch guns were replaced by four 5-inch (127 mm) breech-loading guns. Iron Duke was heavily armored with an 8-inch (203 mm) wrought iron waterline belt covering her entire length, backed by 8-10 inches of teak, with the belt thinned to six inches toward the ends. Her main deck citadel was protected by 5-inch (127 mm) bulkheads, and her sides and battery ends had 6-inch armor. Constructed at Pembroke Dockyard and costing approximately £208,763, she was initially assigned as a guardship and later served as flagship on the China Station, marking her as the first ironclad to navigate the Suez Canal. Her service was marked by several notable incidents, including the accidental sinking of her sister ship Vanguard in 1875 after a collision in fog, and multiple groundings during her Far East deployment. She also participated in fleet reviews and served in various reserve and guard roles before being converted into a coal hulk in 1900. Ultimately, HMS Iron Duke was sold for scrap in 1906, ending a notable career in late 19th-century naval service.

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