Despite its Mark number, this was actually the first 14" (35.6 cm) gun that was exclusively designed and accepted into service by the Royal Navy. Previous 14" (35.6 cm) naval guns had been acquired either by taking over ships and guns building for other nations or by importing USA weapons.

The high-velocity heavy gun had fallen out of favor in the British Navy because of the problems experienced with the 16"/45 (40.6 cm) Mark I used on the Nelson class battleships. For this reason, the design of the new 14"/45 (35.6 cm) Mark VII reverted to the lower velocities used in guns produced before and during World War I. As a result, the muzzle velocity of the new Mark VII did not differ appreciatively from that achieved by the 14"/45 (35.6 cm) Mark I carried by the battleship Canada (ex-Chilean Almirante Latorre) during World War I.

The decision to use 14" (35.6 cm) guns on the King George V class Battleships was made in order to comply with Treaty restrictions, despite the fact that other European powers were building ships with larger weapons. As a result, the King George V class were arguably the weakest-armed battleships built in the 1930 to 1946 time period.

The design of this gun was based upon the 12"/50 (30.5 cm) Mark XIV, which was an experimental weapon completed in August 1933 to test "all steel" construction techniques. These new 14" (35.6 cm) guns were to a no-wire, radial-expansion construction, which resulted in a stronger, lighter gun that was less likely to suffer from barrel droop. This improved design gave the British a weapon that was more accurate and had a longer barrel life than the larger 16"/45 (40.6 cm) Mark I. Unfortunately, the mountings for these weapons were prone to mechanical failures during the early part of the war, with both HMS Prince of Wales and HMS King George V having numerous problems during their engagements against Bismarck.

Many, if not most, of these problems had been corrected by 1943. During the early part of her action against Scharnhorst at the Battle of the North Cape on 26 December 1943, HMS Duke of York made 31 straddles out of 52 broadsides fired and during the latter part she made 21 straddles out of 25 broadsides, a very creditable gunnery performance. In total, Duke of York fired 446 shells in 80 broadsides. However, HMS Duke of York still fired less than 70% of her possible output during this battle because of mechanical and "errors in drill" problems.

A Note on Sources: There are conflicts in the references below as to how many shells and how many broadsides were fired by HMS Duke of York in this action. I have chosen to use those numbers given in "Loss of Scharnhorst" by A.J. Watts which has detailed tables in "Part II - Statistical Data."

In addition to those used on the battleships, a further two guns were used as coastal artillery at Dover, but their extemporized mountings were not suitable for targeting fast moving ships. These coastal guns were supplied with a supercharge, giving them a very long range.

Consisted of tapered inner A tube, A tube, jacket breech ring of rectangular external shape, breech bush located in the A tube and a shrunk collar over the A tube. Used a Welin breech block and hydraulic Asbury mechanism. Including the two trial guns, a total of 78 guns were made, 24 by the Royal Gun Factory, 39 by Vickers-Armstrong, Elswick and 15 by Beardmore. The last 46 guns produced had a different shape to the breech ring which lowered the overall weight of the gun. These latter guns used a 12.5 ton (12.7 mt) counterweight while the earlier guns used a 11 ton (11.2 mt) counterweight in order to maintain the same center of balance. The Mark VII* was a loose barrel version, but none were ever manufactured.

These were the first heavy British guns in service to recoil in a cast steel cradle rather than on slides - in other words, unlike previous guns, these guns did not have a separate slide. This was a feature first prototyped on the 12"/50 (30.5 cm) Mark XIV.

At least one gun still exists and is currently on display at the Royal Armoury located at Fort Nelson, Hampshire, UK. See Additional Pictures below.

• ^The weight given for "Early guns" is for guns No. 51 through 90 which had the original breech ring design. The weight given for "Later guns" is for guns No. 91 through 136 which had the altered breech ring design. In addition to these weights, a balance weight was attached near the breech in order to move the center of gravity closer to the turret face plate. This allowed a higher elevation without having to deepen the gun wells, thus reducing the size of the gunhouse. Including the balance weight, guns No. 61 to 90 weighed 90.588 tons (92.042 mt) and guns No. 91 to 136 weighed 91.488 tons (92.956 mt).

• ^From late 1942 to early 1943, "K" shell was introduced which contained dyes for coloring shell splashes. These shells also had a small fuze and burster to disperse the dye. These items increased the shell weight by 5 lbs. (2.2 kg) and reduced the average gun muzzle velocity by 3 fps (1 mps). The following splash colors are listed in a 20 June 1946 Fleet Order:

     King George V: Yellow
     Duke of York: Green
     Anson: White (this almost certainly means "no dye")
     Howe: Red

• ^APC was 6/12crh.
• ^The propellant charge was in four bags.
• ^The mounting handbook says that new gun MV was 2,475 fps (754 mps) nominal, but recorded velocities are per the figure noted above.
• ^For Treaty compliance purposes, these ships were listed as carrying 80 rounds per gun but they actually had space for 100 rounds.
• ^Shell stowage was a total of 1,100 rounds, including about 10 practice rounds per gun – 432 for 'A' turret, 216 for 'B' and 452 for 'Y'. Cordite stowage was a total of 2,133 cases with two quarter charges per case – 821 in 'A' magazines, 432 in 'B' and 880 in 'Y'.
• ^The original outfit was 100 rounds of APC per gun, but by mid-1943 five of these had been replaced by time-fuzed HE.

Time of flight for APC Shell with MV = 2,400 fps (731.5 mps)
   10,000 yards (9,140 m): 14.1 seconds
   20,000 yards (18,290 m): 32.4 seconds
   30,000 yards (27,430 m): 57.4 seconds 83.2 seconds

• ^The following description is adapted from "Naval Weapons of World War Two."

  Propellant bags were transported from their storage locations in the magazines on roller chutes into hydraulically operated cages that raised them to the handling room. A and B mountings had four cages, but Y turret had two. Y turret had two double-door scuttles in place of the other two hoists, primarily because of the reduced vertical spacing for this mounting. In the handling rooms, bags were manually rolled or slid over to open waiting trays from which they were then manually carried to cordite hoppers. There was one hopper per gun on a circular platform connected to the hoist trunk. Power-rotated scuttles and chain rammers transferred the bags to the lower hoist cage. This cage had two compartments which each held two propellant bags (half charge).

  Projectiles were moved from the shell rooms by overhead trolleys and then rammed over hinged shell trays through openings normally closed by watertight doors to the revolving shell ring in the shell handling room. The shell rings for the quad mountings held 16 trays in four groups spaced 90 degrees apart while the twin mounting had 8 trays in four groups spaced 90 degrees apart. The shell room ring could either be coupled to the ship or to the revolving stalk. When coupled to the ship, the shell ring was driven by a 24 bhp hydraulic engine that was connected via a flexible coupling, friction clutch, worm gear and pinions with allowance for eccentricity and a rise and fall of up to 1 inch (25 mm) of the ring in relationship to the mounting. When coupled to the stalk, a similar hydraulic engine was used but the connection to the shell ring did not have any provision for eccentricity or relative motion. [Editor's note: This ring proved not to be flexible enough to withstand the twisting of the ship as it moved through the waves or made sharp maneuvers and was a source of jamming]  Projectiles were rammed into the upper hoist cage when the ring was coupled to the stalk.

  The lower hoists were operated by winches having two reel drums of different diameters on the same shaft which meant that the propellant and shell cages arrived together at the working chamber below the gunhouse. Projectiles and propellant bags were rammed from the cages into traverses which ran on rails across the chamber to the gun loading hoist cage. This was a three level container with the shell on top and half charges in each of the two lower compartments. The hoist then ran up to the gunhouse at a slant such that the loading cages were at the +5 degree loading angle when they reached the gun breeches. After the shell was rammed, the cage incremented upwards twice as the half charges were rammed.

  Magazines were located below the shell rooms.

• ^These mountings had very elaborate flash precautions, perhaps overly so given the problems encountered during World War II.
• ^Turret stalks had a vertical roller race similar to the ones added to Nelson and Rodney in the 1930s. These were located just below the main horizontal roller races.
• ^"The Big Gun" states that the quadruple mounting had over 3,000 working parts.
• ^Training was by one of two swashplate engines, 160 bhp in the quads and 70 bhp in the twin, which drove the turrets via a worm gear. Elevation was by hydraulic cylinder and piston connected to the rear of the cradle and run out was via compressed air. RPC equipment was never fitted to any of these ships, they used "follow the pointer" style control throughout their careers.
• The gun axes were 96 in (244 cm) apart in both the twin and the quad mountings.
• Rangefinders in A and X turrets had a baselength of 41 feet (12.5m) while the Duplex rangefinder in B turret had a baselength of 30 feet (9.10 m).
• Each turret had vent holes drilled in the rear turret plates. These were covered with light plates designed to blow off in case of an explosion.
• Some details of the problems found in action with these mountings during the 1941 battles: Prince of Wales fired only 55 out of a possible 74 shells during her action with Bismarck. Her problems included jammed shell rings and associated fittings. King George V fired 339 shells during her engagement with Bismarck compared to 380 fired by Rodney.
• The following description of the problems encountered by King George V is taken from "The Final Action: The Sinking of Bismarck, 27 May 1941" by John Roberts:

  "Initially she did well achieving 1.7 salvos per minute while employing radar control but she began to suffer severe problems from 0920 onward [Note: King George V had opened fire at 0850]. 'A' turret was completely out of action for 30 minutes, after firing about 23 rounds per gun, due to a jam between the fixed and revolving structure in the shell room and Y turret was out of action for 7 minutes due to drill errors. . . Both guns in B turret, guns 2 and 4 in A turret and gun 2 in Y turret were put out of action by jams and remained so until after the action - 5 guns out of 10!  There were a multitude of other problems with mechanical failures and drill errors that caused delays and missed salvos. There were also some misfires - one gun (3 of A turret) misfired twice and was out of action for 30 minutes before it was considered safe to open the breech."

  [Note: The ellipsis in this paragraph is to omit what I believe is actually a reference to the performance of Rodney's 16" (40.6 cm) guns which was mistakenly included in this description]

  Admiral Sir John C. Tovey, C-in-C Home Fleet, commented upon some of these problems in his after-action report PRO Adm 234/509:

  "Comparatively little experience had previously been gained of the reliability of the turrets. The prolonged practice firing for the King George V had been carried out only in one turret. It was fortunate that the action [against Bismarck] was not prolonged, because the 25 rounds per gun practice previously planned would not have shown up so many of the defects."

• Following the Bismarck battles, King George V and Prince of Wales had numerous modifications made to their ammunition supply safety interlock system; the watertightness of the mantlet plates was improved; and the existing drains in the shell rooms were enlarged and additional drains fitted. These changes were incorporated into the rest of the class as they were being built.
• During her battle with Scharnhorst at North Cape, Duke of York was shooting for a total of two hours. Mechanical problems suffered included failures of the bridge flash tubes in the working chambers to close completely, the collapse of shell arresters in the lower hoists and a shell-cage defect in A turret, all of which caused some guns to drop out of firing opportunities. All guns suffered at least some failures to fire, with B1 gun being the most reliable, having missed only three out of the 80 broadsides. Notable among these missed salvos: Poor loading drill and a shell cage fault caused A1 to miss 73 broadsides. Three guns in Y turret were unable to fire for a 15 minute period, causing them to miss 17 broadsides. All together Duke of York fired 446 shells but missed 241 firing opportunities during the engagement.
• Some comments from William Jurens regarding the vertical face plates of these turrets.

  "The reason for sloped turret faces is primarily geometric. For normal trunnion locations, if the turret face is not sloped back, then for large angles of [gun] elevation, as in post-1930 ships, the gunports get very large and start to eat away at the turret roof. If the angle of elevation is small as on older ships, [then the] angles of fall [of shells fired by enemy ships] would be equally small, so a slanted faceplate which would deflect rounds upward makes sense. If the angle of elevation is large and a vertical front plate is seen to be desirable, as in KGV etc., then one answer to avoiding cutting long slots in the roofplates is to move the trunnions far forward. This makes the overall rotating structure and the guns themselves harder to balance and complicates gun elevation mechanisms. On KGV a compromise was made; the trunnions were moved as far forward as possible, and the front plate was moved BACK as far as was feasible. Even so, the maximum angle of elevation was limited to 40 degrees. There is little saving in weight in moving to a vertical faceplate, in some cases less than none.

  . . . moving from a sloped to a vertical faceplate is usually nearly weight-neutral, although some savings can be achieved by thinning the vertical face somewhat as it is now much more oblique to incoming (long-range only) fire than a sloped face is. Several problems remain. On KGV, moving the face back left an inconvenient "D" shaped portion of the top of the barbette uncovered forward of the faceplate, a situation aggravated by the probability that long range fire, even if deflected, would be channeled downwards into the "D". On KGV, this "D" underneath the gun chases was about 115 ft² (10.7 m²) in area, which needed to be protected at least as well as the turret roof. This added protection would weigh about 13 additional tons. A final problem lies in the construction of the face plate itself. Such a plate is much stronger if it can be made in one piece with two, three, or four (as required) vertical slots cut into it for gunports. This in turn requires at least a thin band of material above and below the port openings to hold the whole thing together. Because the slots are quite problematical in a vertical plate to begin with, there is a tendency to revert to installing a number of smaller plates joined together, which is not as strong, though arguably cheaper to manufacture.

  Overall, I suspect that vertical faceplates create more problems than they solve, and their advantages (if any) are marginal, which is likely why so few ships ever adopted them."

  As can be seen in the photographs on this datapage, the quad turrets on the King George V class have a semi-circular plate of armor attached to the lower front plate of the turret. This plate protects the top of the barbette. According to ADM 234/271, this was actually a total of about 7.9 inches (20 cm) thick (see Armor note below) so the total added weight was about 17 tons rather than the 13 tons noted by Mr. Jurens above.
• Two guns were mounted as coastal artillery at Dover in 1940, one in No. 26 Proof Structure and the other in a 18"/40 (45.7 cm) mounting removed from a monitor.
• Armor thickness for both twin and quad mountings as given in "Naval Weapons of World War Two" by John Campbell and ADM 234/271:
      Face: 12.74 in (32.4 cm) (520 lbs.)
      Fore Sides: 8.82 in (22.4 cm) (360 lbs.)
      Rear Sides: 6.86 in (17.4 cm) (280 lbs.)
      Rear: 6.86 in (17.4 cm) (280 lbs.)
      Roof: 5.88 in (14.9 cm) (240 lbs.)
      Floor 2.96 in (7.5 cm) (120 lbs.) plus 4.9 in (12.4 cm) (200 lbs.) sill plate in front of the gunhouse to protect the top of the barbette.

Images at The Vickers Photographic Archive. See Quadruple 14

"British Naval Gun Mountings: 18-inch to 4.5-inch BD from 1890" by Ian Buxton
"Naval Weapons of World War Two" and "British Naval Guns 1880-1945 No 1" article in "Warship Volume V" both by John Campbell
"The King George V class - Parts 1 to 4" articles in "Warship Volume III" by Robert Dumas
"Battleships: Allied Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"The Big Gun: Battleship Main Armament 1860-1945" by Peter Hodges
"British Battleships of World War Two" by Alan Raven and John Roberts
"The Final Action: The Sinking of Bismarck, 27 May 1941" article in "Warship Volume VII" by John Roberts
"King George V Class Battleships" by V.E. Tarrant
"Loss of the Scharnhorst" by A.J. Watts
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"Handbook for 14 inch BL Mark VII gun on twin, Mark II and quadruple, Mark III mounting" ADM 234/271
"Shell for 14, 15 and 16 inch guns: Summary of trials; requirements and stocks" ADM 1/25853
"Proceedings of the Ordnance Board 1939 NO. 915"
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Royal Armouries Website
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Special help from Phil Golin, William Jurens, Robert Lundgren, Nathan Okun, Neil Stirling, Zhu Shipeng and Matthew Warwick

14 September 2008 - Benchmark
22 October 2009 - Added details on gun manufacturers, coast guns at Dover, gun weight and new gun muzzle velocity in Ammunition Table
13 December 2009 - Corrected typographical error
09 September 2011 - Added to note about gun weights, added links to other datapages
11 February 2012 - Updated to latest template
03 June 2012 - Added turret armor note
03 November 2012 - Added information on ammunition supply and photograph of Duke of York
15 December 2013 - Added Additional Pictures
04 July 2016 - Converted to HTML 5 format
11 March 2018 - Reorganized notes
24 January 2020 - Added information on Duke of York gunnery
23 June 2020 - Added Duke of York photograph and armor details
28 November 2020 - Redid photograph of quad turret under construction
28 September 2021 - Added turret floor and front of gun house armor protection
17 December 2021 - Added "average gun" muzzle velocity, minor changes
20 February 2022 - Changed APC burster weight, added HE burster weight, ammunition stowage capacity and note about turret vent holes
24 August 2022 - Added information on gun at the Royal Armouries and a Note on Sources
25 February 2024 - Added Shellite as burster explosive
14 March 2024 - Added Turret sketches and description
05 May 2024 - Added photograph of bow turrets on HMS King George V
12 December 2024 - Added HE designation and burster weight