BL 9.2-inch Mk I – VII naval gun
Ordnance BL 9.2-inch Mk I–VII gun | |
---|---|
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 |
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)[1] |
Shell | 380 pounds (172.37 kg)[1] 290 pounds (131.54 kg) (High-angle guns)[2] |
Calibre | 9.2-inch (233.7 mm) |
Muzzle velocity | 2,065 feet per second (629 m/s)[3] |
Maximum firing range | 10,000 yards (9,100 m)[note 1] |
The BL 9.2-inch Mk I–VII guns
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 (9.45 inch) gun at the time. 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.
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 Alexandraas 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
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
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 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
Ammunition
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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.
See also
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
- brown prism powder or 53½ lb corditepropellant 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
- 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
- ISBN 1-8434-2560-2
- 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