HMS Neptune was a dreadnought battleship built for the Royal Navy in the first decade of the 20th century, the sole ship of her class. She was the first British battleship to be built with superfiring guns. Shortly after her completion in 1911, she carried out trials of an experimental fire-control director and then became the flagship of the Home Fleet. Neptune became a private ship in early 1914 and was assigned to the 1st Battle Squadron.
The ship became part of the Grand Fleet when it was formed shortly after the beginning of the First World War in August 1914. Aside from participating in the Battle of Jutland in May 1916, and the inconclusive action of 19 August several months later, her service during the war generally consisted of routine patrols and training in the North Sea. Neptune was deemed obsolete after the war and was reduced to reserve before being sold for scrap in 1922 and subsequently broken up.
Background and description
The launch of in 1906 precipitated a naval arms race when Germany accelerated its naval construction plans in response. Despite this sudden expansion of another nation's fleet, the British Admiralty felt secure in the knowledge that Germany would have only four modern capital ships in commission by 1910, while the Royal Navy would have eleven. Accordingly, they proposed the construction of only a single battleship and a battlecruiser in the 1908–1909 naval budget that they sent to the government in December. The Liberals, committed to reducing military expenditures and increasing social welfare spending, wished to cut the budget by £1,340,000 below the previous year's budget, but were ultimately persuaded not to do so after the Prime Minister, Sir Henry Campbell-Bannerman, was thoroughly briefed on each part of the budget in February 1908. The debates over the budget in March were heated; critics were dissatisfied with the number of ships being built, arguing that the Government was too complacent about the superiority of the Royal Navy over the Imperial German Navy, but they were satisfied when H. H. Asquith, Chancellor of the Exchequer, filling in for the fatally ill Prime Minister, announced that the government was prepared to build as many dreadnoughts as required to negate any possible German superiority as of the end of 1911.
Neptune was an improved version of the preceding with additional armour and the armament rearranged for greater efficiency. She was the first British dreadnought that differed in her gun turret layout from Dreadnought. Unlike the earlier ships, her wing turrets were staggered "en echelon" so all five turrets could shoot on the broadside, although in practise the blast damage to the superstructure and boats made this impractical except in an emergency. This was done to match the 10-gun broadside of the latest foreign designs like the American , although the all-centreline turret configuration of the American ships eliminated the blast problems that compromised the effectiveness of the "en echelon" arrangement. Neptune was also the first British dreadnought to be equipped with superfiring turrets, in an effort to shorten the ship and reduce costs. A further saving in length was achieved by siting the ship's boats on girders over the two wing turrets to reduce the length of the vessel. The drawback to this arrangement was that if the girders were damaged during combat, they could fall onto the turrets, immobilising them. The bridge was also situated above the conning tower, which similarly risked being obscured if the bridge collapsed.
Neptune had an overall length of , a beam of , and a deep draught of . She displaced at normal load and at deep load. The ship had a metacentric height of at deep load. Her crew numbered about 756 officers and ratings upon completion and 813 in 1914.
The ship was powered by two sets of Parsons direct-drive steam turbines, each of which was housed in a separate engine room. The outer propeller shafts were coupled to the high-pressure turbines and these exhausted into low-pressure turbines which drove the inner shafts. The turbines used steam from eighteen Yarrow boilers at a working pressure of . They were rated at and gave Neptune a maximum speed of . She carried a maximum of of coal and an additional of fuel oil that was sprayed on the coal to increase its burn rate. This gave her a range of at a cruising speed of .