Editing St Vincent-class battleship (section)

==Background and description==
The [[British Admiralty|Admiralty]]'s 1905 draft building plan called for four [[capital ship]]s in the 1907–1908 Naval Programme, but the new [[Liberal Party (UK)|Liberal]] government cut one of these ships in mid-1906 and postponed another to the 1908–1909 Naval Programme, pending the conclusion of the ongoing [[Hague Conventions of 1899 and 1907#Hague Convention of 1907|Hague Peace Convention]]. The failure of the Germans to agree to any sort of naval arms control caused the government to reinstate the third ship. The Admiralty took until 12 June 1907 to decide not to build one of them as a [[battlecruiser]], in favour of a [[squadron (naval)|squadron]] of four homogeneous battleships. Three of these would be part of the ''St Vincent'' class, while the single battleship planned for the 1908–1909 Naval Programme was later authorised as {{HMS|Neptune|1909|6}}.<ref>[[#Friedman 15|Friedman (2015)]], pp. 97–102.</ref>

[[File:1stGenBritishBBs.tiff|thumb|left|Right elevation and plan of the first generation of British dreadnoughts from the 1912 edition of ''[[Brassey's Naval Annual]]'']]
The design of the ''St Vincent'' class was derived from the preceding {{sclass|Bellerophon|battleship|4}}, with more powerful guns and a slight increase in size and armour. The ships had an [[length overall|overall length]] of {{convert|536|ft|m|1}}, a [[Beam (nautical)|beam]] of {{convert|84|ft|2|in|m|1}},<ref>[[#Burt|Burt (1986)]], pp. 75–76.</ref> and a normal [[Draft (hull)|draught]] of {{convert|28|ft|m|1}}.<ref name=p5>[[#Preston|Preston (1972)]], p. 125.</ref> They [[Displacement (ship)|displaced]] {{convert|19700|LT|t|lk=on}} at normal load and {{convert|22800|LT|t}} at [[deep load]]. In comparison to the ''Bellerophon'' class, the displacement of the ''St Vincent''s was increased by {{convert|650|LT|t}}, the length by {{convert|10|ft|m|0}} and the beam by {{convert|18|in|cm|0}}; their crews numbered about 755 officers and [[naval rating|ratings]] upon completion and 835 during the war.<ref name="B_76">[[#Burt|Burt (1986)]], p. 76.</ref>

The ''St Vincent''-class ships were powered by two sets of [[Parsons Marine Steam Turbine Company|Parsons]] [[direct-drive]] [[steam turbine]]s, each of which was housed in a separate [[engine room]]. The outer [[propeller shaft]]s were coupled to the high-pressure turbines and these exhausted into low-pressure turbines which drove the inner shafts. Separate cruising turbines were provided for each shaft. The turbines used steam from eighteen [[water-tube boiler]]s at a working pressure of {{convert|235|psi|kPa kg/cm2|0|abbr=on|lk=on}}. They were rated at {{convert|24500|shp|lk=on}} and were intended to give the ships a maximum speed of {{convert|21|kn|lk=in}}. During their [[sea trial]]s, the ''St Vincent''s handily exceeded their designed speed and horsepower, reaching {{convert|21.7|kn}} from {{convert|28,128|shp|abbr=on}}. They carried {{convert|2700|LT|t|0}} of coal and an additional {{convert|850|LT|t|0}} of [[fuel oil]] that was sprayed on the coal to increase its burn rate. This gave them a range of {{convert|6900|nmi|lk=in}} at a cruising speed of {{convert|10|kn}}.<ref>[[#Burt|Burt (1986)]], pp. 31, 64, 76, 80.</ref>

===Armament===
[[File:HMS Vanguard aft guns USNHC NH 52619.jpg|thumb|''Vanguard''{{'}}s starboard aft side, showing her rear 12-inch gun turret and anti-[[torpedo net]] booms, around 1914]]
These ships were the first to carry the new 50-[[caliber (artillery)|calibre]] [[List of British ordnance terms#BL|breech-loading (BL)]] [[BL 12 inch Mk XI - XII naval gun|{{convert|12|in|mm|adj=on|sigfig=3}} Mark XI gun]], which was 5 calibres longer and had a [[muzzle velocity]] about {{convert|75|ft/s|m/s}} higher than the 45-calibre [[BL 12 inch Mk X naval gun|Mark X gun]] used in the earlier dreadnoughts.<ref>[[#Friedman 11|Friedman (2011)]], pp. 59, 62.</ref> They had a reputation for drooping at the [[muzzle (firearms)|muzzle]], which was believed to have an adverse effect at long range, but testing at sea showed the muzzle droop to be within normal tolerances and the accuracy at long range to be satisfactory.<ref>[[#Parkes|Parkes (1990)]], pp. 504–05.</ref> The increased muzzle velocity of the Mark XI gun gave it a longer range over the Mark X gun as well as increasing the distance at which it could penetrate 12 inches of armour from {{convert|7600|to|9300|yd|m|0}} using the same shell. The higher velocity reduced its service life by increasing the wear in the barrel.<ref>[[#Friedman 11|Friedman (2011)]], pp. 59–60, 62–63.</ref>

The ''St Vincent'' class were equipped with ten Mark XI guns in five hydraulically powered twin-[[gun turret]]s, three along the centreline and the remaining two as [[wing turret]]s. The centreline turrets were named 'A', 'X' and 'Y' from front to rear, and the [[port and starboard]] wing turrets were 'P' and 'Q' respectively.<ref name="B_76"/> The guns had a maximum [[elevation (ballistics)|elevation]] of +20° which gave them a range of {{convert|21200|yd|m|0}}. They fired {{convert|850|lb|kg|adj=on|0}} projectiles at a muzzle velocity of {{convert|2825|ft/s|m/s|abbr=on}} at a rate of two [[Cartridge (firearms)|rounds]] per minute.<ref>[[#Friedman 11|Friedman (2011)]], pp. 62–63.</ref> The ships carried between 80 and 100 shells per gun.<ref name="B_76"/>

The [[secondary armament]] of the ''St Vincent''s consisted of twenty 50-calibre [[BL 4 inch naval gun Mk VII|BL four-inch (102&nbsp;mm) Mark VII]] guns. Pairs of these guns were installed in unshielded mounts on the roofs of 'A', 'P', 'Q' and 'Y' turrets and the other dozen were positioned in single mounts at [[forecastle]]-deck level in the [[superstructure]].<ref name=p3>[[#Parkes|Parkes (1990)]], p. 503.</ref>{{refn|Sources disagree on the number, type and composition of the secondary armament. Burt gives only eighteen 4-inch guns and claims that they were the older [[List of British ordnance terms#QF|quick-firing]] QF Mark III guns; he also lists a 12-pounder (three-inch (76&nbsp;mm)) gun.<ref name="B_76"/> Preston concurs on the number of 4 inchers, but does not list the 12 pounder.<ref name=p5/> Parkes says twenty 4-inch guns; while not identifying the type, he does say that they were 50-calibre guns<ref name=p3/> and Preston agrees.<ref>[[#Preston 1985|Preston (1985)]], p. 23.</ref> Friedman shows the QF Mark III as a 40-calibre gun and states that the 50-calibre BL Mark VII gun armed all of the early dreadnoughts.<ref name=f1/>|group=Note}} The guns had a maximum elevation of +15° which gave them a range of {{convert|11400|yd|m|abbr=on|0}} firing {{convert|31|lb|kg|adj=on|1}} projectiles at a muzzle velocity of {{convert|2821|ft/s|m/s|abbr=on}}.<ref name=f1>[[#Friedman 11|Friedman (2011)]], pp. 97–98.</ref> They were provided with 150 rounds per gun; the wartime allowance for each gun was 200 rounds. Four 3-pounder {{convert|47|mm|in|abbr=on|1|order=flip}} [[saluting gun]]s were also carried. The ships were equipped with three [[British 18 inch torpedo|18-inch (450&nbsp;mm)]] submerged [[torpedo tube]]s, one on each [[Broadside (naval)|broadside]] and another in the [[stern]], for which nine [[torpedo]]es were provided.<ref name="B_76"/>

===Fire control===
[[File:St Vincent - NH 54835.jpg|thumb|''St Vincent'' at anchor, before 1912]]
The control positions for the main armament were located in the [[Top (sailing ship)|spotting tops]] at the head of the fore and [[mainmast]]s. Data from a {{convert|9|ft|m|adj=on|1}} [[Barr and Stroud]] [[coincidence rangefinder]] located at each control position, together with the target's speed and course information, was input into a [[Dumaresq]] mechanical computer and electrically transmitted to [[Vickers range clock]]s located in the transmitting station located beneath each position on the main deck. Wind speed and direction was called down to the transmitting station by either [[voicepipe]] or [[sound-powered telephone]]. The range clock integrated all the data and converted it into elevation and [[Deflection (ballistics)|deflection]] data for use by the guns. The target's data was also graphically recorded on a plotting table to assist the gunnery officer in predicting the movement of the target. The turrets, transmitting stations and control positions could be connected in almost any combination.<ref>[[#Brooks 95|Brooks (1995)]], pp. 40–41.</ref> As a backup, two turrets in each ship ('A' and 'Y' in ''St Vincent'') could take over if necessary.<ref>[[#Brooks 05|Brooks (2005)]], p. 61.</ref>

In 1910–1911, the four-inch guns on the roof of the forward turret of ''Vanguard'' were replaced by a {{convert|9|or|12|ft|m|adj=on|1}} rangefinder. This was removed about a year later, roughly at the same time when the rooftop guns were removed from the forward turrets of the other two ships.<ref name=b81>[[#Burt|Burt (1986)]], pp. 80–81.</ref> In late 1914, the remaining rooftop guns were replaced on the three [[sister ship]]s by 9-foot rangefinders protected by armoured hoods.<ref name="dread">Admiralty Weekly Order No. 455 of 6 October 1914, referenced in footnotes 16 and 17, {{cite web |title=St. Vincent Class Battleship (1908) |url=http://www.dreadnoughtproject.org/tfs/index.php/St._Vincent_Class_Battleship_(1908) |publisher=The Dreadnought Project|access-date=4 February 2017 |language=en}}</ref>

[[Fire-control system|Fire-control technology]] advanced quickly during the years between the ''St Vincent''s' commissioning and the start of World War I and the most important development was the [[Director (military)|director]] firing system. Mounted high in the ship, a fire-control director electrically provided data to the turrets via a pointer on a [[dial (measurement)|dial]], which the turret crewmen only had to follow. The director layer fired the guns simultaneously, which aided in spotting the shell splashes and minimised the effects of the [[ship motions|roll]] on the dispersion of the shells.<ref>[[#Brooks 05|Brooks (2005)]], p. 48.</ref> While the exact dates of installation are unknown, ''St Vincent'' was equipped with a director by December 1915 and the others by May 1916.<ref>[[#Brooks 96|Brooks (1996)]], p. 168.</ref> The ships were fitted with Mark I [[Frederic Charles Dreyer#Dreyer Fire Control Table|Dreyer Fire-control Tables]] in the transmission stations by early 1916, which combined the functions of the Dumaresq and the range clock.<ref>[[#Brooks 05|Brooks (2005)]], pp. 157–158, 175.</ref>

===Armour===
The ''St Vincent''-class ships had a [[waterline]] [[Belt armor|belt]] of [[Krupp cemented armour]] that was {{convert|10|in|0}} thick between the fore and aftmost [[barbette]]s that reduced to {{convert|2|in|0}} before it reached the ships' ends. It covered the side of the [[hull (watercraft)|hull]] from the middle [[deck (ship)|deck]] down to {{convert|4|ft|11|in|m|1}} below the waterline where it thinned to {{convert|8|in|0|}} [[amidships]]. Above this was a [[strake]] of 8-inch armour. Transverse [[bulkhead (partition)|bulkheads]] {{convert|5|to|8|in|0}} thick terminated the thickest parts of the waterline and upper armour belts once they reached the outer portions of the endmost barbettes. The three centreline barbettes were protected by armour {{convert|9|in|0}} thick above the main deck and thinned to {{convert|5|in|0}} below it. The wing barbettes were similar except that they had 10 inches of armour on their outer faces. The gun turrets had {{convert|11|in|0|adj=on}} faces and sides with 3-inch roofs.<ref>[[#Burt|Burt (1986)]], pp. 76, 78.</ref>

The three armoured decks ranged in thickness from {{convert|0.75|to|3|in}} with the greatest thickness outside the central [[armoured citadel]]. The front and sides of the forward [[conning tower]] were protected by 11-inch plates, although the rear and roof were 8 inches and 3 inches thick respectively. The aft conning tower had 8-inch sides and a 3-inch roof. The ''St Vincent''s had two longitudinal anti-[[torpedo bulkhead]]s {{convert|1|–|3|in}} thick that extended from the forward end of 'A' barbette to the end of 'Y' [[magazine (artillery)|magazine]]. In the vicinity of the [[boiler room (ship)|boiler rooms]], the compartments between them were used as [[coal bunker]]s.<ref>[[#Burt|Burt (1986)]], pp. 78, 80.</ref>

===Modifications===
[[File:British Battleships of the First World War Q40389.jpg|thumb|''Vanguard'' at anchor, 1910]]
The guns on the forward turret roof were replaced in 1910–1911 by a rangefinder on ''Vanguard'', and on her sisters in 1911–1912. About two years later, [[gun shield]]s were fitted to most of the guns in the superstructure and the [[bridge (nautical)|bridge]] structure was enlarged around the base of the forward tripod mast. During the first year of the war, the base of the forward superstructure was rebuilt to house eight 4-inch guns and the turret-top guns were removed, which reduced their secondary armament to a total of fourteen guns; a pair of 3-inch (76&nbsp;mm) [[anti-aircraft gun|anti-aircraft (AA) guns]] were added. Approximately {{convert|50|LT|t}} of additional deck armour were added after the Battle of Jutland in May 1916. By April 1917, the sisters mounted thirteen 4-inch anti-torpedo boat guns as well as single 4-inch and 3-inch AA guns. The stern torpedo tube was removed in 1917–1918 and ''St Vincent'' was equipped to operate [[kite balloon]]s. In 1918, a high-angle [[Rangefinding telemeter|rangefinder]] was fitted on the forward spotting top of the surviving ships and [[Flight deck#Early|flying-off platforms]] were installed on the roofs of the fore and aft turrets of ''Collingwood''.<ref name=b81/>