BL 6 inch Mk XI naval gun

BL 6 inch gun Mk XI
Gunnery exercise on HMAS Melbourne circa. 1913
Type	Naval gun Coast defence gun
Place of origin	United Kingdom
Service history
In service	1906 - 1950s
Wars	World War I World War II
Production history
Variants	Mk XI
Specifications
Barrel length	300 inches (7.620 m) bore (50 cal)

Shell	100 pounds (45.36 kg) Lyddite, Armour-piercing, Shrapnel^[1]
Calibre	6 inches (152.4 mm)
Muzzle velocity	2,900 feet per second (884 m/s)^[2]
Maximum firing range	18,000 yards (16,000 m) @ 22.5°^[3]

The BL 6 inch Gun Mark XI^[4] was a British 50 calibres high-velocity naval gun which was mounted as primary armament on cruisers and secondary armament on pre-dreadnought battleships from 1906 onwards.

History

The gun with its increased length of 50 calibres gave improved firepower over the current 6-inch Mk VII gun of 45 calibres. However, its increased length and weight made it unwieldy in the current manually operated shipboard mountings on light cruisers, which did not provide a steady platform. Britain reverted to 45-calibres guns in new warships from 1914 onwards with the BL 6 inch Mk XII gun.

Naval gun

Guns were mounted in the following ships :

The last 3 King Edward VII class battleships Britannia, Africa and Hibernia laid down 1902 - 1904
Armoured cruisers: HMS Duke of Edinburgh and Black Prince laid down 1903
Bristol class light cruisers laid down 1909
Weymouth class cruisers laid down 1910
Chatham class light cruisers laid down 1911
Birmingham class light cruisers laid down 1912
Monitor HMS Marshal Ney as re-gunned in 1918

Coast defence gun

Gun and crew at Fort Cowan, Brisbane, November 1943

The Mk XI gun was emplaced for coast defence in South Africa and particularly in Australia leading up to World War II, and remained in service until the 1950s. Guns in Australia came from the decommissioned World War I cruisers HMAS Sydney, HMAS Melbourne and HMAS Brisbane and were emplaced in northern Australia and Torres Strait to defend against possible attack by Japan,^[5]^[6] and on Rottnest Island WA, Brisbane and the Sydney harbour^[7] and Port Kembla^[8] defences.

Surviving examples

One of HMAS Melbourne's guns on display in 2015

RGF gun No. 2035 of 1905, and 1 other gun at Malgaskop, Saldanha Bay, South Africa
VSM gun No. 2305 of 1912 formerly at Port Wakefield Proof Range, north of Adelaide, and since 2006 at B42 gun emplacement at Lower Georges Heights, Sydney Australia^[9]
A coast defence gun at East Point Military museum, Darwin, Australia
EOC gun at Leighton Battery, Fremantle, Western Australia
One of HMAS Melbourne's guns at the Fleet Air Arm Museum

Notes

↑ 100 lb shells : Treatise on Ammunition, 1915
↑ 2900 ft/second : As quoted in "Range Tables for His Majesty's Fleet, 1910. February, 1911"; with 32 lb 1½ oz cordite MD size 26 propellant : Treatise on Ammunition, 1915
↑ 18,000 yards @ 22.5° elevation as coast defence gun, quoted by Spethman, 2008. Guns in naval use had lower elevation and hence shorter range.
↑ Mk XI = Mark 11, i.e. the eleventh model of BL 6-inch guns. Britain used Roman numerals to denote Marks (models) of ordnance until after World War II.
↑ Vanessa Seekee, "Artillery in Torres Strait 1891 - 1945: the silent forgotten sentinels of the north" in Memoirs of the Queensland Museum Cultural Heritage series, Volume 4 Part 1, November 2006
↑ For photograph of gun at Emery Point, Darwin 1934 see ID Number: P02024.026 at Australian War Memorial photo archive
↑ For photograph of gun at Signal Hill 1946 see ID Number: 129982 at Australian War Memorial photo archive
↑ See The Diary and Journal of General Sir John G. N. Wilton, Royal Australian Army 1910 - 1977
↑ http://www.harbourtrust.gov.au/downloads/acrobat/media/mrcoastalgun.pdf

References

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

External links

Wikimedia Commons has media related to BL 6 inch Mk XI naval gun.

Tony DiGiulian, British 6"/50 (15.2 cm) BL Marks XI and XI*

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 US 14 inch 45 cal 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 V 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 pdr 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 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 pdr 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

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