Colossus Class Battleship (1910)

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Overview of 2 vessels
Citations for this data available on individual ship pages
Name Builder Laid Down Launched Completed Fate
Colossus Scotts Shipbuilding and Engineering Company, Greenock 8 Jul, 1909 9 Apr, 1910 8 Aug, 1911 Sold Jul, 1928
Hercules Palmer Shipbuilding and Iron Company, Hebburn 30 Jul, 1909 10 May, 1910 31 Jul, 1911 Sold 8 Nov, 1921


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 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 in The Sight Manual, 1916 except where otherwise noted.[4]

The ten 12-in guns were Mark XI mounted in B. XII turrets. The mountings could elevate 15 degrees and depress 5 degrees.

The gun sights were cam-worked and limited to 15 degrees elevation though the dials were only scaled to 14 degrees. 6 degree super-elevation prisms would have been provided by 1916. They were the first F.T.P. turret sights in Royal Navy use, but otherwise much like the sights in Neptune.

The deflection gearing constant was 70.8, with 1 knot equalling 2.30 arc minutes, calculated as 2850 fps at 5000 yards. Range drums were provided for full charge at 2850 fps, reduced charge at 2300 fps, as well as 6-pdr sub-calibre gun and .303-in aiming rifles.

Muzzle velocity was corrected by adjustable scale plate between +/- 75 fps. The adjustable temperature scale plate could vary between 60 to 100 degrees Fahrenheit,[Fact Check] and a "C" corrector could alter the ballistic coefficient by at least +/- 15% and possibly 20% as in other sights.[Fact Check]

Drift was corrected by inclining the sight bracket by 3 degrees and having 1.3 knots permanent right deflection.

The side position sighting lines were 37.83 inches above and 39.5 inches abreast the bore, and the central scopes were 49.25 inches above and 42 inches abreast.

The hydraulic controls in training reflected the final advance for the Royal Navy, to a seven-cylinder swash-plate engine from Elswick; operated by a single hand wheel, responsive training would permit continual aim in all but the heavy seas. Elevation may have been a little less refined, requiring three turns of a handwheel to reach the maximum 3 degrees per second elevation rate.[5]

Secondary Battery

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

Sixteen 4-in B.L. Mark VII guns on P. IV* mountings were arranged for broadside fire. They were similar to the equipment fitted in Lion, Orion, and Gloucester.

The mounting could elevate 15 degrees and depress 10 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 later P. IV* sights such as in Bellona, these sights were not 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 13.73 inches above the bore, and 15.85 inches left. The trainer's sight line was 15.08 inches above and 14.9 inches right.

The sight had a temperature correcting scale plate and 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, these mountings, along with many other 4-in and 6-in mountings in capital ships were to have illumination added for their training index racers.[7] In August of that 1913, Portsmouth Royal Dockyard was to supply head rests for these guns, to be fitted in the dockyard when the opportunity arose.[8] In October 1913, it was decided that the mountings should also have buzzer for their firing circuits.[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 - so perhaps there had been an increase in allotment between the two original design and the time of the belt-tightening.[11]


  • three 21-in submerged tubes:[12]
    • two broadside tubes forward 12 feet, 7.4375 inches below load waterline, depressed 2 degrees with axis of tube 1 foot 7.5625 inches above the deck.
    • one stern tube 8.5 feet below load WL, depressed 1 degree with axis of tube 1 foot 8.625 inches above the deck.

Also, some number (perhaps about 5, as often provided elsewhere) 14-in Mark X torpedoes for use by boats.[13]

These were the first British battleships to feature 21-in torpedoes.[14]

The torpedoes for the stern tubes were probably removed sometime during or after 1916 to increase numbers available for broadside use in the fleet.[15] The stern tubes themselves were removed in 1917-18.[16]

In early 1914, the ships had one Torpedo Director Pattern 2391 and one Pattern 2392 and were to have them exchanged for -A models which supported gyro angling.[17]

By mid-1917 and likely a considerable time before,[Inference] the ships were provided a Torpedo Control Plotting Instrument Mark I in the T.C.T..[18]

Fire Control

Range Dials

As of 1920, it appears that these dreadnoughts and earlier ones did not receive such equipment, though the Orion class did..[19]


The ships had a rangefinder in the spotting top and another in the aft superstructure.[20] 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.[21]

Sometime during or after 1917, an 9-foot rangefinder on an open mounting was to be added specifically to augment torpedo control. It seems likely that Hercules received hers before Colossus.[22][23]

In 1918, a high angle rangefinder, likely a 2m F.T. 29, was installed over the fore top; the top mast was retained.[24]

Evershed Bearing Indicators

The two units were fitted with this equipment before late 1914, albeit in a slightly different manner.[25]

Colossus's transmitting positions were

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

Hercules's transmitting positions were

  • Conning Tower
  • Fore bridge (transmitters to port and starboard with C.O.S. to select one in use)
  • "A" turret
  • "X" turret

The protocols for handling wooding of the turrets is outlined in the Handbook for Fire Control Instruments, 1914.[26]

In 1917, it was approve 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.[27]

Mechanical Aid-to-Spotter

At some point, both 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.[28]

In 1917, it was decided that these should have mechanical links from the director and pointers indicating the aloft Evershed's bearing.[29]

Gunnery Control

The control arrangements were as follows.[30]

In 1910, it was decided that the telaupad control of the secondary battery in Neptune, Indefatigable, Hercules and Colossus should be replaced with Rudolph voicepipes. Other ships in the Home Fleet had also been experimentally fitted, but a report on a final decision was still pending.[31]

Control Positions

  • Fore top
  • Gunnery control tower
  • "A" turret
  • "X" turret

Some ships had within the control positions so they could be connected to either T.S..[32]

Control Groups

The five 12-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

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 "Y" turret?).[33] The battery was not divisible into groups for split director firing.[34]

The turret Elevation Receivers were pattern number H. 3, capable of matching the 15 degree elevation limit of the mountings. The Training Receivers were the single dial type, pattern number 5.[35]

Secondary Battery

The 4-in guns never had directors installed.[36]

Transmitting Stations

Like nearly all large British ships of the era prior to King George V and Queen Mary,[37] these ships had two transmitting stations.

Dreyer Table

Hercules was equipped with the Original Dreyer Table for some period from 1911 through at least April 1914,[38] brought along with Captain Dreyer when he left Prince of Wales.[39]

The ships eventually each received a Dreyer Table Mark I,[40] but were never given Dreyer Turret Control Tables.[41]

Fire Control Instruments

Breaking a pattern of acquisition dating back to the Bellerophon class, this class used Vickers F.T.P. Mark III range and deflection instruments (with cross-connected Mark III* range transmitters[42]) when sending data to gun sights, retaining Barr and Stroud (probably Mark II*[Inference]) instruments for other destinations.[43]

The ships also had Target Visible and Gun Ready signals to indicate which turrets could see the target and which guns were ready mounted in the TSes and control positions.[44]

Torpedo Control

By the end of 1917, common torpedo control additions to all capital ships were to be adopted where not already in place. Those for Dreadnought and later classes with 18-in tubes were to include:[45]

  • duplication of firing circuits and order and gyro angle instruments to allow all tubes to be directed from either C.T. or T.C.T.
  • navyphones from both control positions to all tube positions
  • bearing instruments between "control position, and R.F., and course and speed of enemy instruments where applicable, between the transmitting stations and the control positions."
  • range circuits between R.F.s and control positions

See Also


  1. Admiralty Weekly Order No. 408 of 25 Sep, 1914.
  2. ARTS 1908 Wireless Appendix, p. 13.
  3. Annual Report of the Torpedo School, 1914. p. 52.
  4. The Sight Manual, 1916. pp. 33-34, 106, 108-109, Plate 10.
  5. Brooks. Dreadnought Gunnery and the Battle of Jutland, pp. 45-46.
  6. The Sight Manual, 1916. pp. 86, 108, Plate 39.
  7. Admiralty Weekly Orders. The National Archives. ADM 182/4. 21 Feb, 1913 entries. pp. 3-4.
  8. Admiralty Weekly Order No. 470 of 22 Aug, 1913.
  9. Admiralty Weekly Order No. 569 of 17 Oct, 1913.
  10. Burt. British Battleships of World War One. p. 157.
  11. Grand Fleet Gunnery and Torpedo Orders. No. 167, part 5.
  12. Addenda (1911) to Torpedo Manual, Vol. III., 1909, p. 155.
  13. Annual Report of the Torpedo School, 1909. p. 14.
  14. Burt. British Battleships of World War One. p. 121.
  15. Annual Report of the Torpedo School, 1916. p. 36. (T.O. 168/1916).
  16. Burt. British Battleships of World War One. p. 128.
  17. Admiralty Weekly Order No. 1019 of 17 Apr, 1914.
  18. Handbook of Torpedo Control, 1916. p. 38. Inference based on Mark II gear being in place in other ships in 1915.
  19. absent from list on Manual of Gunnery of H.M. Fleet, Volume III, 1920, p. 44.
  20. Burt. British Battleships of World War One. p. 121. Burt is clearly mistaken that turret R.F.s were originally fitted.
  21. Admiralty Weekly Order No. 455 of 6 Oct, 1914.
  22. Annual Report of the Torpedo School, 1917. p. 198. (C.I.O. 481/17) mentions Hercules.
  23. Annual Report of the Torpedo School, 1918. p. 176. mentions Colossus.
  24. Burt. British Battleships of World War One. p. 128.
  25. Handbook for Fire Control Instruments, 1914. p. 36.
  26. Handbook for Fire Control Instruments, 1914. p. 36.
  27. Annual Report of the Torpedo School, 1917. p. 230.
  28. The Technical History and Index, Vol. 3, Part 23. pp. 25-6.
  29. Annual Report of the Torpedo School, 1917. p. 230.
  30. Handbook for Fire Control Instruments, 1914. p. 7.
  31. Annual Report of the Torpedo School, 1910. p. 149. (A.L.G. 12731/10/18960 of 16 Aug 1910).
  32. Handbook for Fire Control Instruments, 1914. p. 7.
  33. The Director Firing Handbook. pp. 88, 142.
  34. The Director Firing Handbook. p. 88.
  35. The Director Firing Handbook. pp. 144, 146.
  36. absent from list in The Director Firing Handbook, 1917. pp. 143.
  37. Handbook for Fire Control Instruments, 1914. pp. 6-7.
  38. Admiralty Weekly Orders (ADM 182/5), p. 4.
  39. Pollen Aim Correction System, Part I. p. 12.
  40. Handbook of Captain F. C. Dreyer's Fire Control Tables, 1918. p. 3.
  41. absent from list in Handbook of Capt. F.C. Dreyer's Fire Control Tables, p. 3.
  42. Annual Report of the Torpedo School, 1910. p. 148.
  43. Handbook for Fire Control Instruments, 1914. pp. 72.
  44. Handbook for Fire Control Instruments, 1914. p. 11.
  45. Annual Report of the Torpedo School, 1917. p. 209. (C.I.O. 4212/17.).


  • 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.
  • Dreyer, Frederic; Usborne, Cecil through Gunnery Branch, Admiralty. (1913). Pollen Aim Corrector System, Part I. Technical History and Technical Comparison with Commander F. C. Dreyer's Fire Control System. P. 1024. in Admiralty Library, Portsmouth.

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