Difference between revisions of "Orion Class Battleship (1910)"

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[[File:HMS_Orion_1913.jpg|thumb|600px|'''H.M.S. ''Orion'''''<br>Image courtesy of [https://www.battleships-cruisers.co.uk/ship.php?ShipID=1258 Battleships-cruisers.co.uk]]]
[[File:HMS_Orion_1913.jpg|thumb|600px|'''H.M.S. ''Orion''''' in Portsmouth Harbour, c. 1913.<br>Image courtesy of [https://www.battleships-cruisers.co.uk/ship.php?ShipID=1258 Battleships-cruisers.co.uk]]]
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Revision as of 09:11, 12 December 2019

H.M.S. Orion in Portsmouth Harbour, c. 1913.
Image courtesy of Battleships-cruisers.co.uk
Overview of 4 vessels
Citations for this data available on individual ship pages
Name Builder Laid Down Launched Completed Fate
Conqueror William Beardmore & Company, Parkhead 5 Apr, 1910 1 May, 1911 23 Nov, 1912 Sold 19 Dec, 1922
Monarch Armstrong, Whitworth & Company, Elswick 1 Apr, 1910 30 Mar, 1911 27 Apr, 1912 Sunk 20 Jan, 1925
Orion Portsmouth Royal Dockyard 29 Nov, 1909 20 Aug, 1910 2 Jan, 1912 Sold 19 Dec, 1922
Thunderer Thames Ironworks, Shipbuilding and Engineering Company, Millwall 13 Apr, 1910 1 Feb, 1911 15 Jun, 1912 Sold 17 Dec, 1926


In September 1914, the ships were each to be sent eight 3/9 power telescopes and to return the same number of 2.5 power scopes, Pattern G. 329 upon receipt. These were likely to serve as trainer telescopes. Constrained supplies meant that 26% of the scopes actually supplied her may have wound up being 5/12 or 5/21 scopes.[1]


According to the ambitions of 1909, these ships had Service Gear Mark II wireless upon completion.[2]


The ships (except, seemingly, Thunderer) 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.[3]


Main Battery

This section is sourced from The Sight Manual, 1916 except as otherwise noted.[4]

The ten 13.5-in Mark V(L) guns were in Mark II (or Mark II*) mountings. The sights were similar to those in Lion and Princess Royal.

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 59.47, with 1 knot equalling 2.51 arc minutes, calculated as 2550 fps at 5000 yards. Range drums were provided for full charge at 2500 fps, three-quarter charge at 2100 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%.

These sights were luxuriously equipped with a cam to correct for drift, which afforded a more precise correction than simply inclining the sight. However, the effect of the cam was not to swing the periscope but to alter the position of the index for the deflection dial. It was through use of the deflection handwheel that the periscope would attain the correct adjustment in azimuth.

The side position sighting lines (parenthetically different in Conqueror) were 41.25 (22.35) inches above and 39 (40.2) inches abreast the bore, and the central scopes were 56.25 (35.85) inches above and 42 (43.5) inches abreast. The left-hand centre position sight was a free trainer's sight, able to swing freely in pitch.

O.O.Q. Open Director Sights capable of 20 degrees elevation had been fitted to Orion by 1916, and the others were to be fitted with them.

A box of tools was provided for every 4 sights.

As in the Lion class, the hydraulic controls in training were operated by a single handwheel, able to provide continual aim in most conditions. Elevation also seemed to support continual aim well, and the elevation speed was increased slightly from 3 degrees per second in previous mountings. In 1912, the advance in smooth control of large Royal Navy guns was captured when it was noted that Orion's gunlayers were "able to follow a roll of 12 degrees out to out without difficulty and some a roll of 16 to 18 degrees out to out."[5]

Secondary Battery

This section is sourced in The Sight Manual, 1916.[6]

Orion differed from her sisters in using a P. IV mounting (one source indicated P. IV*);[7] her particulars are documented on her ship's page — the configuration common to the other three is documented here.

Sixteen 4-in B.L. Mark VII guns on P. II* mountings were arranged for broadside fire. They were similar to the P. II and P. II* equipment fitted in the Bellerophon, Neptune, Indefatigable classes and other ships.

The range dial may have been 14 inches in diameter with markings that came closer together at higher ranges, as in the P. II. If so, the marks were 34 inch apart for 50 yards difference at 500 yards and was 18 inch for 50 yards difference at 9,000 yards.

The mounting could elevate 15 degrees and depress 7 degrees, but though its sight could match the 15 degree elevation, the range dial was only graduated to 11.5 degrees (10,000 yards).

These cam-worked sights had range dials for 2750 fps, and 1-in and .303-in aiming rifles. M.V. could be corrected by adjustable pointer through +/- 150 fps.

Unlike earlier P. II* sights such as on Neptune, these sights were F.T.P. sights.

The deflection gearing constant was 64.277 with 1 knot equal to 2.41 arc minutes, corresponding to 2800 fps at 2000 yards. Drift was corrected by inclining the sight 2 degrees.

The layer's sight line was 14 inches above the bore, and 15.25 inches left. The trainer's sight line was 15.25 inches above and 12.5 inches right.

The sight had a temperature corrector, but not a "C" corrector.

The layer had an open sight. The trainer's sight could be used as a free sight with a counterweight.

In February, 1913, the P. II* mountings (but apparently not Orion's P. IV mountings), along with many other 4-in and 6-in mountings in capital ships were to have illumination added for their training index racers.[8] In August of 1913, Portsmouth Royal Dockyard was to supply head rests for all these guns, to be fitted in the dockyard when the opportunity arose.[9]

The original storage was 150 rounds per gun,[10] 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.[11]


The ships had three 21-in submerged torpedo tubes. Orion's broadside tubes were angled at 90 degrees, and the other ships' broadside tubes were angled 10 degrees in advance of the beam.[12]

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 and axis 1 foot, 8.625 inches above the deck.[13]

The torpedoes for the stern tubes were probably removed sometime during or after 1916 to increase numbers available for broadside use in the fleet.[14] There is no indication that the stern tubes themselves were removed as had been done with other classes.[15]

Fire Control

Range Dials

As of 1920, all four ships had a single Range Dial Type D.[16]


The ships carried a rangefinder in the spotting top and another over the aft shelter deck.[17]

The ships did not initially have rangefinders in her turrets, but these were added around October 1914, when armoured hoods were belatedly being prepared for holes recently cut in the roofs.[18]

Sometime during or after 1917, an additional 15-foot rangefinder on an open mounting was added specifically to augment torpedo control.[19]


The Orion class inaugurated use of the new Pattern 246X Navyphones and a new Graham Navyphone Exchange to permit flexible communication. The phones caused a small degree of early problem by exhibiting corrosion where their aluminum alloy case met its brass screws or where salt spray might find it. These defects were remedied in 1912 or so by sleeves for the screws and replacement brass cases for the exposed phones.

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.[20]

Main Battery

Navyphone Circuits for Main Battery[21]
Navyphone Circuits for Main Battery[22]

Both the fore and aft T.S. had direct-wired navyphones to each of the five turrets. Each turret, then, had at least two navyphones in it: one to each T.S.. "B" and "Q" (perhaps scheduled to be changed to "X" in 1914),[Inference] being alternative control positions, each had an additional pair of navyphones to a two-way C.O.S. in the fore T.S. offering these options:

  • Fore T.S. to "B", Aft T.S. to "Q"
  • Fore T.S. to "Q", Aft T.S. to "B"

The transmitting stations were otherwise identical. Each operator of the Range, Deflection and Order instruments addressing a turret had a Patt. 2465 Special Transmitter in parallel with the Pattern 2463 Navyphone for that turret. These were wired to the direct-wired Pattern 2464 Navyphone in the turret and supported five sets of Telaupads (for layers, sightsetters and trainer).

Each 2463 in the T.S. had a switch, when left open, places it in communication with its turret. When closed, the 2463 was connected to a busbar in the TS which could multiplex the 2463s to two groups: ("A" + "B") and ("Q" + "X" + "Y") or, when the busbar's own switch is closed, would cause all turrets to be addressed at once.

This general style of navyphone control was appealing enough that a modified form of it was installed in ships prior to Orion,[23] though it should be noted that eventually cylindrical C.O.S.es were used for this sort of group switching.

It is interesting to note that the navyphone grouping places "Q" with the aft turrets, and the director grouping places "Q" with the forward turrets. It invites speculation as to whether one was subsequently altered to agree with the other.

Secondary Battery

Evershed Bearing Indicators

By 1914, Orion was fitted as follows.[24]

Orion's transmitting positions in late 1914 were

  • Conning Tower
  • Fore control platform (transmitters to port and starboard with C.O.S. to select one in use)
  • "B" turret
  • "Q" turret (scheduled to be changed to "X" turret)

Monarch and Thunderer were equipped later, as noted on their Alterations sections.

The protocols for handling wooding of the turrets is outlined in the Handbook for Fire Control Instruments, 1914.[25]

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.[26]

Mechanical Aid-to-Spotter

At some point, the ships were equipped with a pair of 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.[27]

In 1917, it was decided that these should have mechanical links from the director and pointers indicating the aloft Evershed's bearing.[28]

Gunnery Control

The control arrangements were as follows.[29]

Control Positions

  • Control top
  • G.C.T.
  • "B" turret
  • "Q" turret (perhaps scheduled to be changed to "X" in 1914)[Inference]

Some ships had C.O.S.s within the control positions so they could be connected to either TS.[30]

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


Main Battery

Training and Elevation Circuits[31] For Monarch and ConquerorOrion and Thunderer may have differed.

The ships were fitted with a cam-type tripod-type director in a light aloft tower on the foremast along with a directing gun (in "X" turret for Monarch and Conqueror and likely also the other two).[32][33]

This class was the first in which the main battery could be divided into forward ("A", "B" & "Q") and aft ("X" & "Y") groups for split director control.[34]

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

  1. All turrets on aloft tower
  2. All turrets on directing gun
  3. Forward group on aloft tower, aft group on directing gun

The turret Elevation Receivers capable of matching the 20 degree elevation limit of the mountings, but the Pattern numbers differed among the vessels: Orion had Pattern H. 4., Thunderer had pattern number H. 19, and Conqueror and Monarch had pattern number H. 1. The Training Receivers were the single dial type, pattern number 6 in Conqueror and pattern number 5 in the others.[35]

Secondary Battery

The 4-in guns may never have had directors installed, except perhaps in Orion, which is noted as having 6-in P. VIII Type Elevation Receivers on her guns. These were capable of 15 degrees of elevation, had mechanical tilt correctors and were Pattern F. C. 2.[36]

Transmitting Stations

Like nearly all large British ships of the era prior to King George V and Queen Mary,[37] these ships likely had 2 T.S.es.

Dreyer Table

In March, 1914, Conqueror had a Mark II Dreyer Table, though it was at that time called a "Mark III*" table.[38] Orion also received a Mark II Dreyer Table, but from March 1914, Monarch and Thunderer had Mark III Dreyer Tables.[39][40]

As of June 1918, none of the ships had been provided Dreyer Turret Control Tables.[41]

Fire Control Instruments

Fire Control Instruments[42]

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 (with cross-connected Mark III* range transmitters[43]) and Barr and Stroud (probably Mark II*[Inference]) instruments for other purposes.[44]

The ships also had Target Visible and Gun Ready signals, with indications of which turret could see the target and which guns were ready being visible in the TSs and control positions.[45]

In July 1911, it was decided that Orion and subsequent ships should have the order receivers in turrets relocated from the old position in the central sighting hood to the rear of the turret to be used by the officer of the turret.[46]

In mid 1913, the ships were ordered to re-label the reduced charge weight stamped on their 13.5-in range repeat receiver dials to read 21934 pounds rather than the erroneous figure of 22714 pounds presently in place.[47]

Torpedo Control

In 1916, it was decided that arrangements were to be made that all capital ships with 21-in torpedoes to receive transmitters and receivers so that the T.C.T. could pass the plotted torpedo deflection to the C.T., which could then use a reciprocal set of equipment to send the T.C.T. a deflection to be placed on the sight and range to open fire. The Orion class was also to be equipped with a secondary means for firing broadside from the T.C.T. as well as from the C.T..[48]

By mid 1917 and likely a considerable time before,[Inference] all ships in the class were provided a Torpedo Control Plotting Instrument Mark I in the TCT.[49]

In 1919, it was decided that each ship should each receive a Renouf Torpedo Tactical Instrument Type B.[50] In 1920, it was decided that Orion was to also receive one of the nine Renouf Torpedo Tactical Instrument Type Fs manufactured by Elliott Brothers.[51]

See Also


  1. Admiralty Weekly Order No. 408 of 25 Sep, 1914.
  2. Annual Report of the Torpedo School, 1908. Wireless Appendix, p. 13.
  3. Annual Report of the Torpedo School, 1914. p. 52.
  4. The Sight Manual, 1916. pp. 4, 29-31, 106, 109.
  5. Brooks. Dreadnought Gunnery and the Battle of Jutland, pp. 45-46, citing Captain Craig's report of 15 November 1912, available in Craig Waller Papers.
  6. The Sight Manual, 1916. pp. 7, 89-90, 108, Plate 39.
  7. The Director Firing Handbook. p. 145.
  8. Admiralty Weekly Orders. The National Archives. ADM 182/4. 21 Feb, 1913 entries. pp. 3-4.
  9. Admiralty Weekly Order No. 470 of 22 Aug, 1913.
  10. Burt. British Battleships of World War One. p. 157.
  11. Grand Fleet Gunnery and Torpedo Orders. No. 167, part 5.
  12. Annual Report of the Torpedo School, 1917. p. 190.
  13. Addenda (1911) to Torpedo Manual, Vol. III., 1909, p. 155.
  14. Annual Report of the Torpedo School, 1916. p. 36. (T.O. 168/1916).
  15. Burt. British Battleships fails to mention this in the manner done for others.
  16. Manual of Gunnery (Volume III) for His Majesty's Fleet, 1920. p. 44.
  17. Burt. British Battleships of World War One. p. 136. He is clearly mistaken about turret R.F.s being originally provided..
  18. Admiralty Weekly Order No. 455 of 6 Oct, 1914.
  19. Annual Report of the Torpedo School, 1917. p. 198. (C.I.O. 481/17).
  20. Annual Report of the Torpedo School, 1917. p. 233.
  21. Annual Report of the Torpedo School, 1911. p. 102.
  22. Handbook for Fire Control Instruments, 1914. Plate 57.
  23. Annual Report of the Torpedo School, 1911. p. 102.
  24. Handbook for Fire Control Instruments, 1914. p. 36.
  25. Handbook for Fire Control Instruments, 1914. p. 37.
  26. Annual Report of the Torpedo School, 1917. p. 230.
  27. The Technical History and Index, Vol. 3, Part 23. pp. 25-6.
  28. Annual Report of the Torpedo School, 1917. p. 230.
  29. Handbook for Fire Control Instruments, 1914. p. 7.
  30. Handbook for Fire Control Instruments, 1914. p. 7.
  31. Annual Report of the Torpedo School, 1913. Plate 56.
  32. The Director Firing Handbook. pp. 88, 142.
  33. Annual Report of the Torpedo School, 1913. Plate 56.
  34. The Director Firing Handbook. p. 88.
  35. The Director Firing Handbook. pp. 144-6.
  36. The ships are all absent from list in The Director Firing Handbook, 1917. p. 143, but Orion's elevation receivers are detailed on page 145.
  37. Handbook for Fire Control Instruments, 1914. pp. 6-7.
  38. Admiralty Weekly Order No. 972 of 27 Mar, 1914.
  39. Handbook of Captain F. C. Dreyer's Fire Control Tables, 1918. p. 3.
  40. Admiralty Weekly Order No. 972 of 27 Mar, 1914.
  41. absent from list in Handbook of Capt. F.C. Dreyer's Fire Control Tables, p. 3.
  42. Handbook for Fire Control Instruments, 1914. Plate 68.
  43. Annual Report of the Torpedo School, 1910. p. 148.
  44. Handbook for Fire Control Instruments, 1914. pp. 72.
  45. Handbook for Fire Control Instruments, 1914. p. 11.
  46. Annual Report of the Torpedo School, 1911. pp. 95.
  47. Admiralty Weekly Order No. 263 of 30 May 1913.
  48. Annual Report of the Torpedo School, 1916. p. 145.
  49. Handbook of Torpedo Control, 1916. p. 38. Inference based on Mark II gear being in place in other ships in 1915.
  50. Annual Report of the Torpedo School, 1919. pp. 118, 119.
  51. Annual Report of the Torpedo School, 1920. p. 91.


  • H.M.S. Vernon. Annual Report of the Torpedo School, 1911, with Appendix (Wireless Telegraphy). Copy 15 at The National Archives. ADM 189/31.
  • H.M.S. Vernon. (Feb 1914) Annual Report of the Torpedo School, 1913, with Appendix (Wireless Telegraphy). Copy 42 at The National Archives. ADM 189/33.
  • 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.
  • 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.
  • McBride, Keith. Super-Dreadnoughts: The Orion Battleship Family, Warship 1993.

Orion Class Dreadnought
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