BL 6 inch Mk VII naval gun
| BL 6 inch gun Mk VII | |
|---|---|
| 300px On Mk II carriage, Reninghelst, Flanders, 15 June 1916 | |
| Type | Naval gun Coastal defence gun Heavy field gun |
| Place of origin |  United Kingdom
|
| Service history | |
| In service | 1901 - 1972 (Fort Scratchley) 1915 - 1918 (field use) |
| Wars | World War I, World War II |
| Production history | |
| Designer | Vickers |
| Designed | 1899 |
| Number built | 898 |
| Variants | Mk VII, Mk VIII, Mk XXIV |
| Specifications | |
| Weight | 16,875 pounds (7,654 kg) (gun & breech) 25 tons (gun on field carriage) |
| Barrel length | 269.5 inches (6.845 m) (45 cal) |
| | |
| Shell | Lyddite, HE, Shrapnel 100 pounds (45.36 kg)[1] |
| Calibre | 6 inches (152.4 mm) |
| Rate of fire | 8 / minute[2] |
| Muzzle velocity | 2,525 feet per second (770 m/s)[3]. |
| Maximum range | On Field carriage Mk. II : 13,700 yards (12,530 m) [4] Naval : 14,600 yards (13,350 m) (light charge); 15,800 yards (14,450 m) (heavy charge)[5][6] |
| Filling weight | Lyddite : 13 pounds 5 ounces (6.038 kg) Amatol : 8 pounds 14 ounces (4.026 kg) Shrapnel : 874 balls @ 27/lb[7] |
The BL 6 inch Gun Mark VII (and the related Mk VIII)[8] was a British naval gun dating from 1899, which was mounted on a heavy traveling carriage in 1915 for British Army service to become one of the main heavy field guns in the First World War, and also served as one of the main coast defence guns throughout the British Empire until the 1950s.
Contents
Background
The gun superseded the QF 6 inch gun of the 1890s, a period during which the Royal Navy had evaluated QF technology (i.e. loading propellant charges in brass cartridge cases) for all classes of guns up to 6 inch to increase rates of fire. BL Mk VII returned to loading charges in silk bags after it was determined that with new single-action breech mechanisms a 6-inch BL gun could be loaded, vent tube inserted and fired as quickly as a QF 6 inch gun. Cordite charges in silk bags stored for a BL gun were also considered to represent a considerable saving in weight and magazine space compared to the bulky brass QF cartridge cases.[9]
The gun was introduced on the Formidable class battleships of 1898 (commissioned September 1901) and went on to equip many capital ships, cruisers, monitors, and smaller ships such as the Insect class gunboat which served throughout World War II.[5]
Mk VIII in Naval service was identical to Mk VII, except that the breech opened to the left instead of to the right, for use as the left gun in twin turrets.
Guns were mounted in the following ships :
- Formidable class battleships laid down 1898
- Cressy class armoured cruisers laid down 1898
- Duncan class battleships laid down 1899
- Drake class armoured cruisers laid down 1899
- Monmouth class armoured cruisers laid down 1899
- Challenger second class protected cruisers including HMAS Encounter of 1901
- King Edward VII class battleships Commonwealth, Dominion, Hindustan, King Edward VII, New Zealand laid down 1902
- Devonshire class armoured cruisers laid down 1902
- HMS Tiger, battle cruiser laid down 1912
- Centurion class battleships as re-gunned in 1902
- Iron Duke class battleships laid down 1912
- Humber class monitors as re-gunned in 1914 with guns from HMS Montagu
- M15 class monitor M27 of 1915
- Insect class gunboats of 1915
World War I field gun
They were first sent to France in 1915 mounted on improvised rectangular-frame field carriages designed by Admiral Percy Scott, based on the design he had improvised for 4.7 inch guns in the Second Boer War, and were successful.[10]
However, elevation and hence range was limited with the Scott carriages so a proper carriage, MK II, was introduced early in 1916, allowing elevation to 22°. Carriages Mks III, V and VI also appeared.
It was operated by the Royal Garrison Artillery, as were all the larger guns, in World War I, in batteries of 4 guns.
Following its successful employment in the Battle of the Somme its role was defined as counter-battery fire and also they "were most effective for neutralising defenses and for wire cutting with fuze 106 [a new fuze which reliably burst instantly above ground on even slight contact, instead of forming craters]", also for long-range fire against "targets in depth"[11].
It was superseded by the lighter and longer-range BL 6 inch Gun Mk XIX which was introduced from October 1916 but the Mk VII remained in service to the end of World War I.
Coast defence gun
The 6-inch Mk VII gun, together with the 9.2 inch Mk X gun, provided the main coast defence throughout the British Empire, from the early 1900s until the abolition of coast artillery in the 1950s. Many guns were specially built for army coast defence use, and following the decommissioning of many obsolete cruisers and battleships after World War I, their 6-inch Mk VII guns were also recycled for coast defence.
103[12] of these guns were in service in World War I in coastal defences around the UK. Some of these, together with others at ports around the wider British Empire, played an important defence role in World War II and remained in service until the 1950s. In the German raid on Scarborough, Hartlepool and Whitby on 16 December 1914, a notable action was fought by Durham Company RGA of the Territorial Force at Heugh (2 guns) and Lighthouse (1 gun) batteries defending Hartlepool. They duelled with the German battlecruisers Seydlitz and Moltke (11 inch guns) and Blücher (8.2 inch), firing 112 rounds and scoring 7 hits. The battlecruisers fired a total of 1,150 rounds at the town and the batteries causing 112 civilians and 7 military killed.[13]
A number of new similar guns with stronger barrels which allowed more powerful cordite charges to be used were manufactured for coast defence during World War II, and were designated 6-inch BL Mark XXIV.[14]
World War I Ammunition
See also
- 12px Media related to BL 6 inch Gun Mk 7 at Wikimedia Commons
- List of field guns
- List of naval guns
Surviving examples
- Rotunda, Royal Artillery Museum, London
- A coast defence gun at Newhaven Fort, Sussex, UK
- A gun mounted on the 1904 coast defence emplacement at New Tavern Fort, Gravesend, UK
- 2 coast defence Mk 7 guns at Fort Dunree, Lough Swilly, Ireland
- A gun on field carriage at The Front Museum, Lappohja, Finland
- Fort Ogilvie, Point Pleasant Park, Halifax, Nova Scotia
- VSM gun No. 1553 dated 1901 at Princess Royal Fortress, Albany, Western Australia. Obtained from Bermuda during restoration of the site in the 1980s.
- Barrel 1489 which fired the first Australian shot of WWI, and 1317 which fired the first Australian shot of WWII at Fort Nepean, Victoria
- Mk VII gun dated 1902 at Ile aux Aigrettes, Mauritus
- Fort Siloso at Sentosa Island, Singapore
- [1] Momi, Vuda, Batteries, Viti Levu, Fiji Islands
Notes
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- Dale Clarke, British Artillery 1914-1919. Heavy Artillery. Osprey Publishing, Oxford UK, 2005
- Tony DiGiulian, British 6"/45 (15.2 cm) BL Mark VII 6"/45 (15.2 cm) BL Mark VIII 6"/45 (15.2 cm) BL Mark XXIV
- General Sir Martin Farndale, History of the Royal Regiment of Artillery. Western Front 1914-18. London: Royal Artillery Institution, 1986
- General Sir Martin Farndale, History of the Royal Regiment of Artillery. The Forgotten Fronts and the Home Base, 1914-18. London: Royal Artillery Institution, 1988.
- I.V.Hogg & L.F. Thurston, British Artillery Weapons & Ammunition 1914-1918. London: Ian Allan, 1972.
- Admiral Percy Scott, "Fifty Years in the Royal Navy" published 1919
External links
- Ken Musgrave, Diagram of BL 6inch Mk VII Gun on Mk. 2 Carriage at Landships (scroll to bottom of page)
- Per Finsted, Om den engelske 6-tommers feltkanon 1914-1940 (in Danish)
Template:GreatWarBritishNavalWeapons
- ↑ Shell weights given are filled and fuzed i.e. as fired. 100 pounds (45.36 kg) was standard shell weight in WWI. Some earlier shells had slightly higher weights e.g. Mk IV common lyddite shell weighed 101 pounds (45.81 kg)
- ↑ 8 rounds per minute is the figure given by Vickers. Quoted in Brassey's Naval Annual 1901
- ↑ 2525 ft/s with 100 lb (45 kg) projectile, 23 lb (10 kg) cordite MD size 16 propellant was the standard loading in WWI. The original loading was 20 lb (9.1 kg) of the more powerful cordite Mk I size 20, but Mk I caused greater wear
- ↑ Clarke page 23 quotes 13,700 yd (12,500 m) on the Mk II carriage; General Farndale page 130 quotes 12,000 yards (10,970 m) - this is possibly on the Mk I carriage.
- ↑ 5.0 5.1 Tony DiGiulian, British 6"/45 (15.2 cm) BL Mark VII
- ↑ All figures for 100 pounds (45.36 kg) shell, which was standard in WWI.
- ↑ Figures for WWI field gun. Hogg & Thurston 1972, Page 243
- ↑ Mark VIII's breech opened to the left and Mark VII's opened to the right, allowing for paired mounts. Guns mounted singly were all the right-opening Mark VII
- ↑ Treatise on Ammunition 10th Edition 1915, page 393
- ↑ Hogg & Thurston 1972, Page 144
- ↑ Farndale 1986 page 158, quoting War Office Artillery Notes No. 4 - Artillery in Offensive Operations, January 1917.
- ↑ Farndale 1988, Page 404
- ↑ Farndale 1988, Pages 368-369, 401.
- ↑ DiGiulian
