Editing St Vincent-class battleship (section)

===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"/>