King George V Class Battleship (1911)

Overview of 4 vessels
Citations for this data available on individual ship pages
Name	Builder	Laid Down	Launched	Completed	Fate
Ajax	Scotts Shipbuilding and Engineering Company, Greenock	27 Feb, 1911	21 Mar, 1912	31 Oct, 1913	Sold 9 Nov, 1926
Audacious	Cammell Laird, Birkenhead	Feb, 1911	14 Sep, 1912	21 Oct, 1913	Mined 27 Oct, 1914
Centurion	Devonport Royal Dockyard	16 Jan, 1911	18 Nov, 1911	1 May, 1913	Scuttled 9 Jun, 1944
King George V	Portsmouth Royal Dockyard	16 Jan, 1911	9 Oct, 1911	16 Nov, 1912	Sold Dec, 1926

Radio

According to the ambitions of 1909, these ships had Service Gear Mark II wireless upon completion.

Searchlights

The ships were fitted with Siemens' No. 3 Twin Mountings for 24-in projectors. In 1914, these were to be modified to permit 90 degree elevation for use in anti-aircraft work.

Protection

• Belt: 12 inches from 16 feet and 10.5 inches above waterline to 3 feet 4 inches below it, extending between the fore and aft barbettes
• Belt extended obliquely to "A" and "Y" barbettes with 10" protection
• Upper strake: above belt, 9 inches
• Barbettes: 9-10 inches above main deck, tapering to 3-7 inches lower down
• Decks: 1-4 inches
• Conning Tower: 11 inches, roof 3 inches
• Gunnery Control Tower: 4 inches
• Torpedo Control Tower: 6 inches, 3 inch roof
• Forward Secondaries: 3-3.5 inches
• Turrets: 11 inches on faces and sides, and 3-4 inches on roofs

[TO BE CONTINUED - TONE]

Armament

Main Battery

This section is sourced from The Sight Manual, 1916 except as otherwise noted.

• ten 13.5-in Mark V(H) guns were in Mark II mountings able to elevate 20 degrees and depress 5 degrees.

The sights were cam-worked and limited to 15 degrees elevation, but the central sights had "20 degree super-elevation strips". Additionally, 6 degree super-elevation prisms would have been provided by 1916.

The deflection gearing constant was 61.3, with 1 knot equalling 2.51 arc minutes, calculated as 2500 fps at 5000 yards. Range drums were provided for full charge at 2450 fps, three-quarter charge at 2000 fps, as well as 6-pdr sub-calibre gun and .303-in aiming rifle. Muzzle velocity was corrected by adjustable scale plate between 2560 and 2260 fps. The adjustable temperature scale plate could vary between 40 to 100 degrees Fahrenheit, and a "C" corrector could alter the ballistic coefficient by +/- 20%.

As in the Queen Elizabeth class, the periscope holder was inclined 1 degree 37 minutes (which may have effectively been 2.5 degrees for mechanical reasons; it equalled .195 degrees at 10,000 yards) to correct for drift. This design did not require the sightsetter to follow a motion of the deflection index to apply it as was required by the system used in Orion.

The side sighting scopes were 43.25 inches above and 39 inches abreast the bore except in Ajax where they were offset 39.5 inches laterally. The central scopes were offset 56.25 inches above and 42 inches abreast.

O.O.Q. open director sights capable of 20 degrees elevation were fitted to King George V and Emperor of India by 1916, with others slated to follow.

The guns were capable of continual aim in all but heavy weather. Gunlayer and turret trainer each used a single hand wheel. Elevation at a little over 3 degrees per second was achieved by three revolutions of the hand wheel — a sprightliness that was nearing the pinnacle achieved by Iron Duke and Tiger classes.

The original storage was 100 rounds per gun.

Secondary Battery

This section is sourced from The Sight Manual, 1916.

• twelve 4-in B.L. Mark VII guns on P. VI mountings.

The mounting could elevate 15 degrees and depress to 7 degrees, but the sight could only elevate 14 degrees (11,000 yards full charge). By 1916 or so, prisms might have permitted 20 degree firing.^[Inference]

The sight was a cam-worked design with range dials provided for 2750 fps and 1-in and .303-in aiming rifles. M.V. could be corrected by a adjustable pointer +/- 150 fps.

Only the sights in Centurion, not those of her two surviving sisters, were F.T.P. in 1916, though the sights were amenable to this alteration.

The deflection gearing constant was 59.73 with 1 knot equal to 2.41 arc minutes, corresponding to 2750 fps at 2000 yards. Drift was corrected by inclining the sight bracket 2 degrees.

The sight lines were 13 inches above the bore, and 11.5 inches to each side.

The sight had temperature and "C" correction by adjustable plates, but no open sights.

The original storage was to be 150 rounds per gun, but after the Battle of Jutland, when alterations to increase protection forced weight-savings to compensate, the ammunition allotment for these guns was to be reduced to 150 rounds per gun and 6 shrapnel rounds, perhaps not meaning any decrease.

Torpedoes

The ships had three submerged 21-in tubes. The broadside tubes bore 10 degrees before the beam.

The broadside tubes forward were depressed 2 degrees and were 14 feet, 1.8125 inches below load waterline with the tube axis 2 feet, 1.1875 inches above the deck. The stern tube was depressed 1 degree and was 8.5 feet below load WL with its axis 1 foot, 8.625 inches above the deck.

The torpedoes for the stern tubes were probably removed sometime during or after 1916 to increase numbers available for broadside use. The stern tubes themselves were removed in 1917-1918.

Fire Control

Phones and Voicepipes

In early 1914, these ships (with the possible exception of King George V) had a voicepipe between T.S. and G.C.T..

In July 1914, the ships were to receive Pattern 556 Headpieces and Pattern 555 Receivers for their turret navyphones, bringing them up to the standard established in Ajax.

By mid-1918, it was approved to fit Pattern 3331 Navyphones with loud-sounding bells in the auxiliary machinery compartments of Lion and Orion classes and later where existing navyphones have proven ineffective.

Range Dials

As of 1920, King George V and Centurion had three Range Dial Type As and Ajax had two Type As and a Range Dial Type C.

Rangefinders

While she was still building, a 15-foot Barr and Stroud rangefinder (possibly an F.T. model) was purchased for Ajax, to be placed in an armoured hood atop her "B" turret.

The ships eventually featured an improved outfit of rangefinders, carrying:

• two 18-ft rangefinders in turrets (seemingly, "B" and "X")
• three 9-ft rangefinders in the other turrets
• one 9-ft in G.C.T.
• one 9-ft on forebridge
• one 15-ft on top of G.C.T.
• one 15-ft on top of T.C.T.

An additional medium-base rangefinder was added over the conning tower sometime between 1916 and 1919. T. 6]] (High Angle)

By 1921, the ships were equipped as follows:

• "A" and "Y" turrets: 18ft F.T. 24 or F.T. 25 on M.G. 8 mounting
• "B", "Q" and "X" turrets: 9ft F.T. 8 on M.G. 3
• Fore top: 9ft F.Q. 2 on M.P. 2
• Fore bridge: 9ft F.Q. 2 on M.Q. 1
• Argo tower: 9ft F.Q. 2 inside on Argo Mounting, 15ft F.T. 24 on top rear on M.G. 8
• Signal deck: 2m F.T. 29 on M.T. 6 (High Angle)

Evershed Bearing Indicators

Evershed Installation
Showing "X" as a transmitting position.

Most of the units were likely fitted with this equipment before late 1914, except Ajax, who was approved only during 1916.

The transmitting positions (for the 1914 ships, minimally) were

• C.T. (periscope transmitters adapted to receive to port and starboard with C.O.S. to select one in use)
• G.C.T. (rangefinder transmitter fitted to Argo rangefinder)
• "B" turret
• "X" turret

The receiving positions were

• all five turrets had both an open-face and a turret trainer's indicator
• the periscopes in the CT each had an open-face indicator. The one selected on the local C.O.S. would indicate the received bearing
• the G.C.T. had an open-face indicator

The protocols for handling wooding of the turrets is outlined in the Handbook for Fire Control Instruments, 1914.

In 1917, it was approved that capital ships of Dreadnought class and later should have Evershed equipment added to their C.T., able to communicate with either the fore top or the G.C.T.. If there were not enough room in the C.T., a bearing plate with open sights and 6-power binoculars would be added to the C.T.. At the same time, all directors were to be fitted with receivers and, "as far as possible", ships were to have fore top, G.C.T. and controlling turrets fitted to transmit as well as receive, though this was noted as being impossible in some earlier ships.

Mechanical Aid-to-Spotter

At some point, all ships were equipped with two Mechanical Aid-to-Spotter Mark Is, one on each side of the foretop, keyed off the Evershed rack on the director. As the need for such gear was apparently first identified in early 1916, it seems likely that these installations were effected well after Jutland.

In 1917, it was decided that these should have mechanical links from the director and pointers indicating the aloft Evershed's bearing.

Gunnery Control

The control arrangements were as follows.

Control Positions

• G.C.T.
• "B" turret
• "X" turret

Some ships had C.O.S.es within the control positions so they could be connected to either T.S..

Control Groups

The five 13.5-in turrets were each a separate group with a local C.O.S.^[Inference] so that it could be connected to

• Forward T.S.
• After T.S.
• Local control from officer's position within turret

Directors

Main Battery

Training and Elevation Circuits
As shown in Annual Report of the Torpedo School, 1913.

The ships were fitted with a cam-type tripod-type director in a light aloft tower on the foremast atop the spotting top, along with a directing gun in "X" turret.

The main battery could be divided into forward ("A", "B" and "Q") and aft ("X" and "Y") groups for split director control.

A C.O.S. in the T.S. afforded these options:

• All turrets on aloft tower
• All turrets on directing gun
• Forward group on aloft tower, aft group on directing gun

The turret Elevation Receivers were pattern number H. 1, capable of matching the 20 degree elevation limit of the mountings. The Training Receivers were the single dial type, pattern number 6 for Ajax and pattern number 5 for the others.

Secondary Battery

The 4-in guns never had directors installed.

Transmitting Stations

These ships discarded the second T.S. found in earlier dreadnoughts and relied on a single T.S..

Dreyer Table

In late March, 1914, Ajax, Centurion and Audacious had Mark II Dreyer Tables, though they were then referred to as "Mark III*" tables. King George V differed by having a Mark III Dreyer Table. As of June 1918, they had not been provided Dreyer Turret Control Tables.

Fire Control Instruments

Continuing the pattern established in the Colossus class, all 4 units used Vickers F.T.P. Mark III range and deflection instruments to the gun sights and Barr and Stroud (probably Mark II*^[Inference]) instruments for other purposes.

The ships had Gun Ready signals in the T.S. and control positions, but were the first dreadnoughts to discontinue the use of Target Visible signals that appeared in earlier classes.

In 1916, it was decided that Lion and King George V classes and later should receive instruments such that the fore top could be interchangeable as a gun control position with the G.C.T..

Torpedo Control

Alternative Torpedo Director Position
Planned as additions in 1910-1911, these were found in 1915 to be too susceptible to gun blast.

By late 1915, Centurion was fitted with a Torpedo Control Plotting Instrument Mark I in the T.C.T.. King George V and Ajax were fitted some time before mid 1917. It is unlikely that Audacious ever received such equipment.^[Inference]

Between late 1915 and mid 1917, the remaining ships in the class were provided a Torpedo Bearing Plotting Instrument Mark I in the T.C.T..

The ships had small armoured hoods fitted and enjoyed frontal protection from the ship's side armour. A 4-inch embrasure as drawn here gave a line of sight from 70 degrees before to 80 degrees abaft the line of the tube, but this was later modified before construction to do 80 degrees on either side of the tube. Hinged shutters allowed the embrasure to be closed when not in use, and the stand for the director could be swiveled to match any gyro angle in use at the tube.

Torpedo Control in King George V

The T.C.T. had a rangefinder with object glasses in an armoured hood which was dedicated to torpedo control (G. 0639/12). The tower also had a Forbes Speed Indicator. From 1913, it was planned to also equip it with a deflection plotting system of indeterminate type as there was no yet a proven system to choose.

The T.C.T. was to use its own equipment to determine the range, course and speed (or deflection) of the enemy and then to transmit it to all torpedo positions by Barr and Stroud instruments. A C.O.S. in the Transmitting Station permits its transmitters, rather than the T.C.T.'s to supply this data.

The broadside tubes could be fired either from the C.T. or from secondary torpedo control positions in armoured hoods on the beam, situated directly over the broadside tube. The tubes received gyro angles and orders from either the C.T. or their secondary control position, as determined by C.O.S.es in the torpedo flat. The stern tube could only be fired from the T.C.T., and so had no C.O.S..

The broadside tubes had voicepipes to both the C.T. and to their secondary control position. A navyphone with a special transmitter connected the T.C.T. to the stern tube.

The T.S. had 4 navyphone connections to the C.T., the T.C.T. and to the two secondary torpedo control positions at port and starboard. The T.C.T. had a voicepipe as well as a navyphone connecting it to the C.T. and a navyphone to the G.C.T.. Additionally, navyphones at the ship's exchange could be used as alternatives to the hard-wired network.

In all, the system is a condemning illustration of the Royal Navy's absurd over-emphasis on torpedo armaments in their capital ships. At most, one could expect a single torpedo tube to be pointing toward an enemy, and we see the context created to realize its puny threat if we count up the hardware that would have no use without the torpedo outfit remained in place:

1. 3 torpedo tubes and stocks of torpedoes
2. 2 floodable spaces, one large and transverse
3. 2 dedicated director positions
4. 12 dedicated navyphones
5. 2 exchange navyphones
6. 5 triggers
7. 6 C.O.S.
8. 1 Forbes Speed Indicator
9. 10 gongs
10. 3 circuit breakers
11. 4 voice pipes
12. 8 orders instruments
13. 6 gyro angle instruments
14. 8 course and speed instruments
15. 8 range instruments
16. personnel to maintain and serve this equipment
17. space taken up in C.T. and T.S.

In 1916, a number of further changes were decided upon:

• Navyphone communication between C.T. and aft torpedo flat and T.C.T. and fore torpedo flat
• removal of secondary director hoods
• "transfer of instruments in the secondary positions" to the C.T. and T.C.T.. I presume that "secondary positions" means the secondary director hoods.

By 1917-1918, a number of common Torpedo Control equipment packages were to be provided to those ships not already sporting them. Those for the 21-in torpedo ships follow.

Torpedo Control Data between C.T. and T.C.T..

The data instruments to be wired between C.T. and T.C.T. to share range, order and deflection data provided a single deflection transmitter in the T.C.T. so that the results of the torpedo plot to be sent to the single deflection receiver in the C.T. for the information of the Torpedo Control Officer. Conversely, a combined range and deflection transmitter forward allowed the T.C.O. to send back the deflection and intended firing range to the secondary T.C.O. in the T.C.T..

Torpedo Control Evershed

The 21-in torpedo ships were also to be provided with Evershed transmitters in the C.T. and a receiver at the torpedo rangefinder in the T.C.T. in order to ensure that it was obtaining data on the intended target. Limited "slit space" in the C.T. required that the customary binocular-based transmitters be foregone in favour of placing the transmitter on or below the floorboards and to drive it by a shaft from a Torpedo Deflection Sight Mark IV. A control key on the transmitter allowed it to indicate when it was controlling the remote rangefinder or not.

Finally under the 1917-1918 mandate, sufficient instruments were to be provided to permit the Fore Bridge to communicate with the tubes.

In 1919, it was decided that each ship should each receive a Renouf Torpedo Tactical Instrument Type B, with King George V to also receive one of the first nine Renouf Torpedo Tactical Instrument Type Fs manufactured by Elliott Brothers, though that last Type F was reallocated to other purposes in 1920.

In mid-1920, it was envisaged that each remaining ship should receive a single Torpedo Control Disc Mark III* and a pair of mounting brackets to be installed in their primary torpedo control position.

Early in 1923, all Mark II-II**** torpedoes had their low speed performance downgraded to 23 knots to 13,000 yards – 1,000 yards less than previously. This required issuance of a new deflection disc for Torpedo Control Disc Mark III* numbered T. 226A to all ships carrying these weapons, meaning ships of the Iron Duke and King George V classes, as well as H.M.S. Thunderer.

Rangefinders

The rangefinder in the T.C.T. was a initially a 9-foot F.T. 24 on an M.Q. 10 mounting.

Sometime, likely not before 1918, these were to be upgraded to 15-foot instruments, probably also F.T. 24s, with new armoured hoods and racers and training driving the hood directly rather than through the rangefinder mounting. These rangefinders lacked hand-following gear to facilitate in transmission of range cuts, and when it was considered as an addition around 1917, space concerns were causing issues.

By 1918, the desire for torpedo control rangefinders was so keen that the ships were told to save their 9-foot instruments upon receipt of their 15-foot models, as new mountings would be sent so that the 9-foot instrument could be mounted elsewhere.

See Also

• Wikipedia

Bibliography

• H.M.S. Vernon. Annual Report of the Torpedo School, 1912, with Appendix (Wireless Telegraphy). Copy 17 at The National Archives. ADM 189/32.
• Admiralty, Technical History Section (1919). The Technical History and Index: Fire Control in H.M. Ships. Vol. 3, Part 23. C.B. 1515 (23) now O.U. 6171/14. At The National Archives. ADM 275/19.
• Admiralty, Gunnery Branch (1914). Handbook for Fire Control Instruments, 1914. G. 01627/14. C.B. 1030. Copy 1235 at The National Archives. ADM 186/191.
• Brooks, John (2005). Dreadnought Gunnery and the Battle of Jutland: The Question of Fire Control. Oxon: Routledge. ISBN 0714657026. (on Amazon.com and Amazon.co.uk).
• Admiralty, Gunnery Branch (1917). The Director Firing Handbook. O.U. 6125 (late C.B. 1259). Copy No. 322 at The National Archives. ADM 186/227.
• Admiralty, Gunnery Branch (1918). Handbook of Captain F. C. Dreyer's Fire Control Tables, 1918. C.B. 1456. Copy No. 10 at Admiralty Library, Portsmouth, United Kingdom.
• Dumas, Robert. The King George V Class, Warship, Volume III Issues 9-12.