Duncan Class Battleship (1901)

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In 1907, battleships of the Majestic, Canopus, London, and Duncan classes, along with armoured cruisers of the Powerful, Drake, Cressy, Monmouth and Devonshire classes were to land their searchlights from their tops and obtain two additional 24-inch models from their dockyards for placement on the shelter or boat deck. These were to be augmented by (or further upgraded to?) a pair of 36-in searchlights when they became available.[1]


During the war, along with those of other older ships, the eight 6-inch guns casemated on the first deck proved of little use in practical sea states. It was decided to remove the eight casemate guns, plate their ports over and move four of them to the upper deck. Four of the twelve 12-pdr guns were also surrendered due to this alteration.[2]

Main Battery

The four 12-in guns were Mark IX, mounted in twin B VI turrets.[3]

Secondary Battery

Originally, the ship was provided twelve 6-in/45 B.L. Mark VII guns, eight in casemates and four on the upper deck. During the war, this was reduced to eight such guns on the upper deck.[4]

Other Guns

Twelve 12-pdr guns, later reduced to eight when the 6-in casemate guns were relocated.


Fire Control

The general system of wiring between the TSs in ships prior to Lord Nelson class is illustrated in Handbook for Fire Control Instruments, 1914.[5]

The equipment in Montagu is open to conjecture owing to her loss in 1906.


Evershed Bearing Indicators

It is not known if this equipment was ever provided.


These ships never received directors for main or secondary batteries.[6]

Gunnery Control

The ships' guns were organized in 3 groups:[7]

  1. Two 12-in turrets
  2. Starboard 6-in guns ("A" & "X")
  3. Port 6-in guns ("B" & "Y")

Local Control in Turrets

There was no provision in these ships for local turret control wherein the receivers in the turret could be driven by transmitters in the officer's position at the back of the turret.[8]

Transmitting Stations

According to Frederic Charles Dreyer, Exmouth's Gunnery Officer in 1903, the ship at that stage had no T.S.es, no means of communicating ranges and deflections, and just a single 4.5-foot rangefinder. These innovations were maturing and seeing retrofits in the 2-3 years following.[9]

By 1914 at least, these ships had acquired fore and aft transmitting stations.[10]

A C.O.S. allowed control options of

  1. Fore
  2. After
  3. Separate

Each control group had transmitters (of various type, see below) with a pair of receivers, one wired directly to the transmitter as a tell-tale, and the other fed off the wires going to the distant guns (i.e., the aft guns for the fore T.S. and vice-versa) as a repeat. "These repeat receivers are necessary to keep the idle transmitters in step; when changing back from separate control they are required to enable both halves of the group to be set alike before being paralleled on to one transmitter."[11]

Dreyer Table

These ships never received Dreyer tables.[12]

Fire Control Instruments

By 1909, the ships in this class fell into two or three categories for fire control instruments.

The simplest category is just Montagu, for which no information has been found.

The second group, Albemarle, Cornwallis and Duncan, was outfitted with Vickers, Son and Maxim instruments with Barr and Stroud rate instruments:[13]

  • Vickers range transmitters: 6
  • Vickers deflection transmitters: 6
  • Vickers combined range and deflection receivers: 6
  • Vickers C.O.S.: 3
  • Vickers Check fire switches: 6
  • Barr and Stroud rate transmitters: 4
  • Barr and Stroud rate receivers: 8
  • Siemens turret fire gongs: 8 with 2 keys
  • Vickers fire gongs: 12 with 4 keys
  • Captain's Cease Fire Bells: 18 with 1 key (supplier not stated)

Lastly, Exmouth and Russell were fitted with Barr and Stroud Mark II for range and rate, Mark I for orders, and Vickers for deflection:[14]

  • Range (B. & S. Mark II): 6 transmitters (12 in Exmouth), 32 receivers
  • Orders (B. & S. Mark I): 6 transmitters (12 in Exmouth), 22 receivers
  • Rate (B. & S. Mark II): 4 transmitters, 8 receivers
  • Deflection (Vickers): 6 transmitters (12 in Exmouth), 26 receivers (30 in Exmouth)

Additionally, this class had the following Siemens fire control equipment:[15]

  • Group Switches: 3 (converted by Chatham)
  • Turret fire gongs: 8 with 2 keys
  • Fire Gongs: 12 (76 in Exmouth) with 4 keys
  • Captain's Cease Fire Bells: 18 with 1 key

It appears that Exmouth's extraordinary number of instruments was a consequence of her finding herself the proving ground for such instruments.[Citation needed]

These ships lacked Target Visible and Gun Ready signals.[16]

Torpedo Control

See Also


  1. Annual Report of the Torpedo School, 1907. p. 35. The location for each ship type was placement stipulated in C.N.2 11884/13066, 13.12.1906.
  2. Technical History and Index Vol. 4, Part 36, p. 9.
  3. The Sight Manual, 1916, p. 109.
  4. Technical History and Index Vol. 4, Part 36, p. 9.
  5. Handbook for Fire Control Instruments, 1914, p. 50 & Plates 50 and 54(I).
  6. The Director Firing Handbook. pp. 142-3.
  7. Handbook for Fire Control Instruments, 1914. p. 8.
  8. Handbook for Fire Control Instruments, 1914. p. 50.
  9. Dreyer. The Sea Heritage. p. 47.
  10. Handbook for Fire Control Instruments, 1914. p. 50 & Plates 50 and 54(I).
  11. Handbook for Fire Control Instruments, 1914. pp. 50-1.
  12. Handbook of Capt. F.C. Dreyer's Fire Control Tables, p. 3.
  13. Handbook for Fire Control Instruments, 1909. pp. 56-7, 60.
  14. Handbook for Fire Control Instruments, 1909. pp. 56-7, 59.
  15. Handbook for Fire Control Instruments, 1909. p. 59.
  16. Handbook for Fire Control Instruments, 1914. p. 11.


  • Admiralty, Technical History Section (1920). The Technical History and Index: Alteration in Armaments of H.M. Ships during the War. Vol. 4, Part 34. C.B. 1515 (34) now O.U. 6171/20. At The National Archives, Kew, United Kingdom.
  • 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.

Duncan Class Pre-dreadnought
  Albemarle Cornwallis Duncan  
  Exmouth Montagu Russell  
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