HMS Iron Duke was a battleship of the Royal Navy, the lead ship of her class, named in honour of Arthur Wellesley, 1st Duke of Wellington. She served as the flagship of the Grand Fleet during the First World War, including at the Battle of Jutland. For the majority of the Great War, she was based with the rest of the Grand Fleet at
Iron Duke was launched on 12 October 1912 at
The Iron Duke class ships were 189.9 metres (622 feet 9 inches) long overall, and had a beam of 27.4 m (90 ft) and a draught of 8.8 m (29 ft). This was an increase of 7.7 m (25 ft) in length and .3 m (1 ft) in width over the preceding King George V class ships. The Iron Dukes displaced 25,400 tonnes (25,000 long tons). This was some 2,032 tonnes (2,000 tons) heavier than the preceding King George Vs, and was primarily due to the increase in calibre of the secondary battery.
Iron Duke was the first British battleship to be mounted with anti-aircraft weaponry. In 1914, two 3 in (7.62 cm) QF guns were fitted to the aft superstructure, primarily to defend against German airships. The guns fired between 12–14 rounds per minute, and were expected to fire approximately 1,250 shells before replacement or repair was necessary. The shells fired were 5.67 kg (12.5 lb) with a high-explosive warhead. They were manually operated, and had a maximum effective ceiling of 7,160 m (23,500)
In 1931, after the London Naval Treaty, Iron Duke was disarmed and she served as a gunnery training vessel. "B" and "Y" turrets and the torpedo tubes were removed, two 4 in (100 mm) AA guns were mounted and another AA gun was mounted in place of the "B" turret. In 1939, another twin 4.5 in (110 mm) turret was mounted at the "X" turret.
During the Second World War, she was used as a base ship at