BL 9.2-inch Mk I – VII naval gun

Ordnance BL 9.2-inch Mk I–VII gun
Ordnance BL 9.2-inch Mk I–VII gun
	Mk VI gun on disappearing mounting at Ben Buckler Gun Battery, Sydney
Type	Naval gun; Coast defence gun
Place of origin	United Kingdom
Service history
In service	1881–1918
Used by	Royal Navy; Australian colonies
Wars	World War I
Production history
Variants	Mk I – VII
Specifications
Mass	Mk I & II : 20 tons barrel & breech; Mk III : 24 tons; Mk V–VII : 22 tons
Barrel length	Mk I & II : 230 inches (5,842 mm) bore & chamber (25 calibres); Mk III–VII : 290 inches (7,366 mm) (31.5 calibres)
Shell	380 pounds (172.37 kg); 290 pounds (131.54 kg) (High-angle guns)
Calibre	9.2-inch (233.7 mm)
Muzzle velocity	2,065 feet per second (629 m/s)
Maximum firing range	10,000 yards (9,100 m)

The BL 9.2-inch Mk I–VII guns^{[note 2]} were a family of early British heavy breechloading naval and coast defence guns in service from 1881 to the end of World War I. They were originally designed to use the old gunpowder propellants.

History

Mk I and II

British 9.2 inch guns originated from a request by the Admiralty in 1879 for a gun comparable to Krupp's 24 cm MRK L/25.5, a very powerful 9.45 inch gun tested in August 1879. The Admiralty submitted its request to the Committee on Ordnance, which was considering returning to breech-loading artillery after Britain's brief return to muzzle-loaders in the 1860s and 1870s. A new breech-loading gun with a 9.2-inch (234 mm) bore, firing a 380-pound projectile was calculated to be suitable.^[4] A total of 19 Mk I and Mk II guns of 26 calibres were made starting in 1881, but after lengthy delays and modifications they proved unsatisfactory and none made it to sea.

Mk III – Mk VII

The 31.5 calibres versions, Mk III through to Mk VII became the first to be mounted on ships and deployed in general service.

Naval service

Guns equipped the following ships :

Imperieuse-class armoured cruisers launched in 1883 : Mk III
Orlando- class armoured cruisers launched 1886 : Mk V & VI
Blake-class protected cruisers launched 1889 : Mk VI
Edgar-class protected cruisers launched 1890 : Mk VI
HMS Alexandra as re-gunned in 1891
HMS Rupert as re-gunned in 1892
M15-class monitors M19 – M28 launched 1915 : Mk VI guns from Edgar-class cruisers.

Coast defence gun

Most Mk IV guns and some Mk VI guns were used in coast defences.

In the mid-to-late 1880s successful trials were carried out with RML 9-inch coast-defence guns firing at high angles in order to test the effectiveness of plunging fire on decks of ships. When surplus BL 9.2 inch Mk IV and Mk VI guns became available in the 1890s they were likewise adapted to high-angle carriages, with their obsolete 3-motion breech mechanisms replaced by modern continuous-motion patterns to allow faster loading. Locations included Hawkins Battery near Plymouth and Gibraltar.^[5]

The elevation of up to 45° meant that the shell was at risk of slipping back after being rammed forward as only the copper driving band held the shell in place in a BL gun, and they had not been designed to operate at such high angles. The solution adopted was to develop a special high-angle reduced-charge cartridge with a hollow up the centre, through which the gunner inserted a 1+1⁄4-inch-diameter (32 mm) stick about 40 inches long made of beech wood, to prevent the projectile from slipping back before firing. A "light" 290-pound (130 kg) shell was used for high-angle firing, rather than the standard 380-pound (170 kg) shell.^[6]

In the late 19th century to early 20th century five Mk IV coast-defence guns were installed at Singapore : two at Fort Connaught on Blakang Mati, one at Fort Siloso on Sentosa Island and two at Fort Pasir Panjang on Singapore Island.^[7] Two of these remain at Fort Siloso.

World War I railway gun

HMS *Iron Duke*, a Mk III* or Mk VI gun in action at Maricourt, Battle of the Somme, September 1916

From 1915 onwards Elswick adapted a small number of Mk III, Mk IV and Mk VI guns, and mounted them on railway truck mountings for service on the Western Front in France and Belgium.^[8]

Australian service

In the late 1880s and early 1890s the Australian colonies between them ordered 10 barrels and nine carriages for BL 9.2 inch Mk VI 'counter bombardment' disappearing guns:^[9]

New South Wales : Three went to protect Sydney Harbour, plus an extra barrel. Of these, one went to Ben Buckler Gun Battery, one to Signal Hill Battery, and one to Steel Point Battery. The barrel of the gun that had been installed at Signal Hill Battery survives on public display at the Royal Australian Artillery Museum at North Fort, North Head. The gun and carriage of the Ben Buckler gun were unearthed in 1984 and await restoration.
Victoria : Four guns went to Victoria to protect Port Phillip, with two going to Fort Nepean and two going to Fort Queenscliff.
South Australia : In 1888, South Australia purchased two guns for what was to be Fort Glenelg to protect Adelaide, South Australia. However, the residents of Glenelg, concerned that they might become a military target, were able to block construction of the Fort and so the guns were never installed. The British government bought them back in 1915.^[10]^[11]

Ammunition

Ammunition for early Armstrong 25 calibres gun
Palliser shell
Boxer shrapnel shell

Surviving examples

2 Mk IV guns at Fort Siloso, Sentosa Island, Singapore
EOC Mk VII gun No. 7318 dated 1881, originally mounted at Signal Hill, Vaucluse at Royal Australian Artillery National Museum, North Head, Sydney, Australia
A previously buried disappearing gun at Ben Buckler, Sydney, awaiting restoration Archived 31 December 2007 at the Wayback Machine

One Mark I located in Port Royal, Jamaica, on the shores at Fort Charles. Stamped with Mark I 9.2 inch 22 ton gun lying next to its battery and Powder House. Taken out of service after the 1907 earthquake.

Notes

^ 10,000 yards refers to naval mountings which had limited elevation : Text book of gunnery, 1902. Coast and rail mountings allowed greater elevation and hence range.
^ i.e. Marks 1 to 7. Britain denoted marks (models) of ordnance using Roman numerals until after World War II.

References

^ ^a ^b ^c Text Book of Gunnery 1902, Table XII Page 336
^ Treatise on Ammunition 10th Edition 1915
^ 380 lb shell, with 164 lb brown prism powder or 53½ lb cordite propellant size 30. Text Book of Gunnery 1902. 175 lb brown powder is quoted for the Mk V gun in Text Book of Gunnery 1887.
^ Hogg & Thurston 1972, page 164
^ Hogg & Thurston 1972, page 167
^ Treatise on Ammunition 10th Edition, published 1915. Pages 77, 142. High-angle cartridges were 44lb 12 oz or 16 lb 1 oz cordite MD, firing a 290-pound shell.
^ "The Gun Museum. 9.2-inch BL guns". Archived from the original on 11 January 2010. Retrieved 15 July 2010.
^ Hogg & Thurston 1972, page 168-170
^ David Spethman, "The Garrison Guns of Australia 1788–1962", published by Ron H Mortensen, Inala, QLD 2008. ISBN 978-0-9775990-8-0
^ P.A. Richardson, 1987, Fort Glenelg: The Fort that Never was, University of Adelaide.
^ "Heritage Branch Website - Online Database". Archived from the original on 24 October 2008. Retrieved 18 January 2009.

Bibliography

Text Book of Gunnery, 1887. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE Archived 4 December 2012 at archive.today
Text Book of Gunnery, 1902. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE Archived 12 July 2012 at archive.today
Treatise on Ammunition, 10th Edition 1915. War Office, UK. Facsimile reprint published by Imperial War Museum and Naval & Military Press, 2003. ISBN 1-8434-2560-2
Hogg, I.V. and Thurston, L.F. (1972). British Artillery Weapons & Ammunition 1914–1918. Ian Allan, London. ISBN 0-7110-0381-5
Tony DiGiulian, British 9.2"/31.5 (23.4 cm) Marks III to VII

External links

Video : Demonstration of breech operation
"Instructions for 9.2-inch Breech Loading Armstrong Gun, and Automatic Barbette Centre Pivot Mounting" instructions for 25.5 calibre Armstrong gun, apparently as supplied to Australian colonies. From National Archives of Australia
Tony DiGiulian, Britain 9.2"/26 (23.4 cm) Mark I 9.2"/26 (23.4 cm) Mark II

[4] 10,000 yards refers to naval mountings which had limited elevation : Text book of gunnery, 1902. Coast and rail mountings allowed greater elevation and hence range.

[5] .e. Marks 1 to 7. Britain denoted marks (models) of ordnance using Roman numerals until after World War II.

[Gunnery1902-1] Text Book of Gunnery 1902, Table XII Page 336

[2] Treatise on Ammunition 10th Edition 1915

[3] 380 lb shell, with 164 lb brown prism powder or 53½ lb cordite propellant size 30. Text Book of Gunnery 1902. 175 lb brown powder is quoted for the Mk V gun in Text Book of Gunnery 1887.

[6] Hogg & Thurston 1972, page 164

[7] Hogg & Thurston 1972, page 167

[8] Treatise on Ammunition 10th Edition, published 1915. Pages 77, 142. High-angle cartridges were 44lb 12 oz or 16 lb 1 oz cordite MD, firing a 290-pound shell.

[9] "The Gun Museum. 9.2-inch BL guns". Archived from the original on 11 January 2010. Retrieved 15 July 2010.

[10] Hogg & Thurston 1972, page 168-170

[11] David Spethman, "The Garrison Guns of Australia 1788–1962", published by Ron H Mortensen, Inala, QLD 2008. ISBN 978-0-9775990-8-0

[12] P.A. Richardson, 1987, Fort Glenelg: The Fort that Never was, University of Adelaide.

[13] "Heritage Branch Website - Online Database". Archived from the original on 24 October 2008. Retrieved 18 January 2009.

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v t e British Empire naval weapons of the Victorian era
Smoothbore muzzle-loading cannons	18-pounder 24-pounder 32-pounder 55 cwt 32-pounder gun 68-pounder Somerset cannon
Smoothbore muzzle-loading shell guns	8-inch 10-inch 86 cwt
Mortars	10-inch Blomefield 13-inch Blomefield
Howitzers	12-pounder Millar 24-pounder Millar
Rifled breechloaders (Armstrong)	RBL 9 pounder RBL 20-pounder RBL 40-pounder RBL 7-inch 110-pounder
Rifled muzzle-loaders (Lancaster)	68-pounder Lancaster gun
Rifled muzzle-loaders (converted)	RML 64-pounder 71 cwt
Rifled muzzle-loaders (Woolwich)	RML 9-pounder 8 cwt RML 64-pounder 64 cwt RML 7-inch RML 8-inch RML 9-inch RML 10-inch RML 11-inch RML 12-inch 25-ton RML 12-inch 35-ton RML 12.5-inch RML 16-inch
Breech-loaders (new pattern)	BL 4-inch BL 5-inch BL 6-inch 80-pounder BL 6-inch Mk II – VI BL 8-inch BL 9.2-inch Mk I – VII BL 9.2-inch Mk VIII BL 10-inch BL 12-inch Mk I – VII BL 12-inch Mk VIII BL 13.5-inch BL 16.25-inch
Quick-firing guns	QF 3-pounder Hotchkiss QF 6-pounder Hotchkiss QF 6-pounder Nordenfelt QF 12-pounder 12 cwt Mk I QF 4-inch QF 4.7-inch QF 6-inch
Light weapons	Gatling gun Gardner gun Nordenfelt gun 1-inch Nordenfelt gun
Torpedoes	Whitehead torpedo

v t e British Empire naval weapons of the First World War
Monitor guns	BL 9.2-inch Mk VI BL 9.2-inch Mk VIII BL 9.2-inch Mk X BL 9.2-inch Mk XII BL 12-inch Mk VIII BL 14-inch Mk II (US built) BL 15-inch Mk I BL 18-inch Mk I
Capital ship main armament	Vickers 10-inch 45 cal. EOC 10-inch 45 cal. BL 12-inch Mk VIII BL 12-inch Mk IX BL 12-inch Mk X BL 12-inch Mk XI & XII EOC 12-inch 45 cal. Mk XIII BL 13.5-inch Mk I – IV BL 13.5-inch Mk V BL 13.5-inch Mk VI EOC 14-inch 45 cal. Mk I BL 15-inch Mk I
Armoured cruiser main armament	BL 7.5-inch Mk I BL 9.2-inch Mk X BL 9.2-inch Mk XI
Secondary armament and light cruiser main armament	QF 12-pounder 18 cwt QF 14-pounder Maxim-Nordenfelt QF 14-pounder Mk I & II QF 4-inch Mk III BL 4-inch Mk VII QF 4-inch Mk V BL 4-inch Mk IX BL 5.5-inch Mk I QF 6-inch Mk I – III BL 6-inch Mk VII BL 6-inch Mk XI BL 6-inch Mk XII BL 6-inch Mk XIII-XVIII BL 7.5-inch Mk II – Mk V
Destroyer and small cruiser armament	QF 12-pounder 12 cwt Mk II QF 4-inch Mk III BL 4-inch Mk VIII QF 4-inch Mk IV BL 4.7-inch Mk I
Merchant ship armament	QF 4.7-inch Mk I – IV QF 4.7-inch Mk V*
Submarine guns	BL 4-inch Mk XI QF 4-inch Mk XII
Anti-aircraft guns	QF 2-pounder "pom-pom" Mk II QF 3-inch 20 cwt QF 4-inch Mk V
Light weapons	.303 Vickers machine gun QF 3-pounder Hotchkiss QF 3-pounder Vickers QF 6-pounder Hotchkiss
Torpedoes	18-inch Mk V – VIII 21-inch Mk II 21-inch Mk IV
Mines	Spherical Mk I, II and III Vickers Elia mine Type H mine
Anti-submarine weapons	Type A Depth charge Type B Depth charge Type C Depth charge Type D Depth charge Type E Depth charge Type F Depth charge Type G Depth charge Cruiser Mine 7.5-inch howitzer
Landing guns	QF 12-pounder 8 cwt