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BL 12-inch Mk I – VII naval gun

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Ordnance BL 12 inch gun Mk I - VIIte
On HMS Conqueror
TypeNaval gun
Coastal gun
Place of originUnited Kingdom
Service history
In service1882–1920
Used byRoyal Navy
Production history
VariantsMks I - VII[note 1]
Specifications
Mass
  • Mk I : 47 tons barrel & breech
  • Mk II - V 45 tons[1]
  • Mk VI, VII : 46 tons
Barrel length
  • Mk I & II : 301.7 inches (7.663 m) bore (25.14 calibres)
  • Mk III - VII 303 inches (7.696 m) bore (25.25 calibres)[2]
Shell714 pounds (324 kg)[1]
Calibre12-inch (304.8 mm)
Muzzle velocity
  • 1,910 feet per second (582 m/s) 714 lb projectile, with 295 lb Brown Prismatic powder[3]
  • 1,914 feet per second (583 m/s) with 295 lb brown powder or 88 lb 8 oz cordite size 30 charge.[2]
Effective firing range8,000 yards (7,300 m) at 9° 57'[4]

The BL 12 inch naval gun Mk I was a British rifled breech-loading naval gun of the early 1880s intended for the largest warships such as battleships and also coastal defence. It was Britain's first attempt to match the large guns being installed in rival European navies, particularly France, after Britain transitioned from rifled muzzle-loading guns to the modern rifled breech-loaders somewhat later than the European powers. Mks I - VII[note 1] all had a barrel of approximately 303 inches in length (25.25 calibres) and similar performance.

Development

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Context

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After the British government returned to using muzzle-loading guns in 1864/5, it was quite content with its muzzleloaders made by the Royal Arsenal at Woolwich. In the mid 1870s the arsenal was probably ahead in 'chambering' guns. A chambered gun had a chamber with a higher diameter than that of its barrel. This allowed a higher charge, but necessitated a longer barrel to 'consume' that charge. The long guns that Krupp tested in Meppen in 1878 and 1879 then proved that muzzle loading had become a dead end.[5]

At the time, the United Kingdom was not without experience in manufacturing breechloaders. In February 1877, the Elswick Ordnance Company had tested its breechloading EOC 12-inch L/23.5. In mid 1878 it had tested its chambered BL 6-inch 80-pounder gun.[6] In December 1878, the EOC's chambered 8-inch breechloader was tested in Woolwich. When EOC became aware of Krupp's 24 cm MRK L/25.5, tested in Meppen in 1879, it started to develop a 9-inch gun of 18 tons.[7] Meanwhile Vavasseur of the smaller London Ordnance Works was busy manufacturing all steel breechloaders.[8]

The 43 tons guns

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The Royal Arsenal then began to develop a 12-inch breechloader. It meant that the arsenal did not follow the usual practice of first testing new developments (breechloading, longer barrels) with smaller calibers. The urgency to switch to breechloading for the Royal Navy's battleships might explain this. By July 1880, a 12-inch rIfled breech-loading gun of 43 tons was in advanced state of construction.[9]

Later in 1880, a 43 tons gun was mentioned as being prepared at Woolwich for trial. It was 358 inches (9.1 m) inch long and meant to use a charge of 285 pounds (129 kg) of P2 powder to fire a projectile of 714 pounds (324 kg). Other guns being prepared were a 10.4-inch 26 tons gun and a 9.2-inch 18 tons gun. By then EOC had received an order for 14 BL 6-inch 80-pounder gun and one 43 tons breechloader.[10] In December 1880, the 43 tons gun fired two shots at the proof butts with charges of 200 pounds (91 kg) and 250 pounds (110 kg).[11]

In April 1881, there was another heated debate in parliament about the guns for the Royal Navy. George Trevelyan, Parliamentary and Financial Secretary to the Admiralty assured British Parliament that the new battleships HMS Conqueror, Edinburgh (1882) (ex-Majestic), Collingwood (1882), and Colossus (1882) would all carry the 43 ton gun.[12]

When HMS Conqueror was launched on 8 September 1881, a strange note by Trevelyan was cited. It said that on 24 May last year (prob. 1880), Sir William Armstrong had been invited to make a 43 ton breechloader, which had been completed on August 11. Also that two of these guns would be used to arm Conqueror.[13]

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Mk II was installed on battleships Colossus (1882) from 1882, Collingwood (1882) and the coastal service ironclad Conqueror (1881). Mk II guns failed in service and were quickly replaced by Mks III. IV and V, with many changes and improvements. The later marks were also mounted on Hero (1885), sistership of Conqueror, and on Edinburgh (1882), sister ship of Colossus.

Coast defence gun

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Mks I, VI and VII were coast defence versions with trunnions for mounting on recoil slides. They were installed in forts in England at Spitbank Fort, No Man's Land Fort and Horse Sand Fort from 1884 onward and were in active service during World War I.[14]

Ammunition

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See also

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Notes

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  1. ^ a b Mk I = Mark 1, Mk VII = Mark 7. Britain used Roman numerals to designate marks (i.e. models) of ordnance until after World War II. Hence this article describes the first seven models of British BL 12-inch guns

References

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  1. ^ a b Mackinlay 1887, p. Table XVI, Pages 312–313.
  2. ^ a b Ordnance College 1902, p. Table XII, Page 336.
  3. ^ Mackinlay 1887, p. Table XVI, Page 313.
  4. ^ Mackinlay 1887, p. Table XIV, Pages 308.
  5. ^ Orde Brown 1881, p. 66.
  6. ^ Inglis 1880, p. 169.
  7. ^ Simpson 1880, p. 734.
  8. ^ Simpson 1880, p. 42.
  9. ^ Inglis 1880, p. 185.
  10. ^ Army and Navy Journal 1880, p. 421.
  11. ^ Army and Navy Journal 1880, p. 441.
  12. ^ Army and Navy Journal 1880, p. 897.
  13. ^ The Marine Engineer 1881, p. 147.
  14. ^ Hogg & Thurston 1972, p. 188-189.

Bibliography

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  • "Foreign Intelligence". The Journal of the Armed Forces. Vol. XVIII. Army and Navy Journal Incorporated. 1880. pp. 421, 441.
  • "Foreign Intelligence". The Journal of the Armed Forces. Vol. XVIII. Army and Navy Journal Incorporated. 1881. p. 897.
  • Handbook for the 12-inch B.L. 47 ton gun Mark I, VI, VII. Her Majesty's Stationery Office. 1891.
  • Hogg, I.V.; Thurston, L.F. (1972), British Artillery Weapons & Ammunition 1914-1918., Ian Allan, London, ISBN 0-7110-0381-5
  • Inglis, T. (1880). "Targets for the Trial of Recent Battering Ordnance". Professional Papers of the Corps of Royal Engineers. IV. The Royal Engineer Institute: 169–194.
  • Mackinlay, George (1887). Text Book of Gunnery. Her Majesty's Stationery Office.
  • "Her Majesty's ship Conqueror". The Marine Engineer. Whitehall Technical Press: 147–148. 1 October 1880.
  • Orde Brown, C. (1881). "Lessons to be learned from Krupp's Meppen Experiments of 1879". Journal of the Royal United Service Institution. XXIV. W. Mitchell and Co., London: 61–80.
  • Ordnance College (1902). Text Book of Gunnery. Her Majesty's Stationery Office.
  • Simpson, E. (1880). "Wants of the Navy - Cannon I - III". Naval Organization and Administration: Pamphlet Collection. The United Service. p. 647–54.
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