BL 7.5-inch Mk II – V naval gun

Ordnance BL 7.5-inch gun Mk II - Mk V
Turrets for HMS Shannon under construction at the Vickers Works, Barrow
Type	Naval gun Coast defence gun
Place of origin	United Kingdom
Service history
In service	1905–20
Used by	Royal Navy British India
Wars	World War I
Production history
Variants	Mks II, II, II*, III, IV, V
Specifications
Weight	14½ - 16 tons barrel & breech
Barrel length	375 inches (9,520 mm); (50 calibre)

Shell	200 pounds (90.7 kg)
Calibre	7.5 inches (191 mm)
Muzzle velocity	2,765 to 2,840 feet per second (843 to 866 m/s)^[1]
Maximum firing range	14,200 yards (13,000 m)^[2]

The BL 7.5-inch guns Mk II - Mk V^{[note 1]} were a variety of 50-calibre naval guns used by Britain in World War I. They all had similar performance and fired the same shells.

History

Mark II

Mark II guns were originally developed to suit India's coast defence requirements. During World War I several reserve guns made for India but still in the UK were employed as coast defence guns in the UK. They were scrapped or sent to India soon after the war.^[3]

Marks II*, II**, V

Starboard secondary Mk V battery on HMS Minotaur

These were built and employed specifically as naval guns and were mounted as secondary armament as a heavier alternative to 6-inch guns, on the following ships :

Warrior-subclass armoured cruisers HMS Warrior, HMS Cochrane, HMS Achilles and HMS Natal laid down 1903–04, commissioned 1906–07
Minotaur-class armoured cruisers laid down 1905, commissioned 1908–09

Mark III

Forward port Mk III casemate guns on Swiftsure, Gallipoli 1915

Mk III gun from Swiftsure being transported in Belgium in 1917. Photo by Ernest Brooks.

Mark III guns were built by Elswick Ordnance to arm the battleship Constitución they were building for Chile. Britain acquired them by default when she bought Constitución in 1903 to avoid the risk of the ship being acquired by Russia. Constitución became HMS Swiftsure in British service.

Swiftsure was decommissioned in 1917 and her guns were used for coast defence in Britain, as siege guns on the Belgian coast near Nieuport for attacking German batteries, and on M15-class monitors.

Mark IV

Mark IV guns were made by Vickers for the battleship Libertad they were building for Chile. Britain acquired them by default in 1903 when she bought Libertad together with Constitución. Libertad became HMS Triumph in British service.

Surviving examples

1906 R.G.F. gun on Elephanta Island

Two Mk II coast-defence guns made by E.O.C. in 1905 and R.G.F. in 1906, on Elephanta Island, Mumbai, India. Photographs on Flickr

Notes

↑ Britain used Roman numerals to designate versions or models ("Mark" abbreviated as "Mk") until after World War II. Hence this articles covers the second through fifth model/version/Mark of British BL 7.5-inch naval guns

References

↑ Mk II (coast defence) : 2840 ft/second with 62 lb 12 oz cordite MD size 26 (Special for India)(Hogg & Thurston 1972 page 151); Mk II* & V : 2800 ft/second with 61 lb cordite MD size 26 ; Mk III & IV : 2765 ft/second with 54 lb 4 oz cordite MD size 26 (Range Tables for His Majesty's Fleet, 1910 February, 1911) & Treatise on Ammunition 1915.
↑ Mk II coast defence gun. Hogg & Thurston 1972, p. 151
↑ Hogg & Thurston 1972, p. 150

Bibliography

Hogg, I.V. and Thurston, L.F. (1972). British Artillery Weapons & Ammunition 1914-1918. Ian Allan, London.
Tony DiGiulian, British 7.5"/50 (19 cm) Mark III 7.5"/50 (19 cm) Mark IV
Tony DiGiulian, British 7.5"/50 (19 cm) Mark II 7.5"/50 (19 cm) Mark V

External links

Wikimedia Commons has media related to BL 7.5 inch Mk II - V naval gun.

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

British Empire Small Arms & Ordnance of the First World War

No. 1
No. 2 Hales Pattern
Nos. 3, 20, 24, 35 Hales rifle grenades
Nos. 5, 23, 36 Mills
No. 6
Nos. 8, 9 Jam Tin
No. 13 Battye
No. 14 Pitcher
No. 15 Ball
No. 16 Oval
No. 17 Opera hat
No. 18
No. 19
No. 21 "Spherical"
No. 22 Newton-Pippin
No. 25 Sangster
No. 27
No. 28 Chemical
No. 29 Gas
No. 31 Day Signal
No. 32 Night Signal
No. 32 "Spherical E"
No. 34 Egg
No. 37
No. 39 Steuart Pattern

Artillery

Tank guns	QF 6 pounder Hotchkiss QF 6 pounder 6 cwt

Infantry guns	1.59-inch Breech-Loading Vickers Q.F. Gun, Mk II ("Vickers-Crayford rocket gun")

Field Artillery	BL 12 pounder 6 cwt QF 12 pounder 8 cwt QF 12 pounder 18 cwt QF 13 pounder BL 15 pounder BLC 15 pounder QF 15 pounder QF 18 pounder QF 4 inch gun Mk III BL 4 inch gun Mk VII QF 4.5 inch Howitzer

Mountain artillery	RML 2.5 inch Mountain Gun BL 10 pounder Mountain Gun BL 2.75-inch Mountain Gun QF 2.95 inch Mountain Gun QF 3.7-inch mountain howitzer

Howitzers, medium, and heavy artillery	QF 4.7 inch Gun BL 5 inch Howitzer BL 5.4 inch Howitzer BL 60 pounder gun BLC 6 inch siege gun BL 6 inch Gun Mk VII BL 6 inch Gun Mk XIX BL 6-inch 26 cwt howitzer BL 6-inch 30 cwt howitzer BL 8 inch Howitzer Mk I - V BL 8 inch Howitzer Mk VI - VIII

Siege artillery	BL 7.5 inch Mk III naval gun BL 9.2-inch howitzer BL 9.2 inch Mk X naval gun BL 12 inch Howitzer BL 12 inch Mk X naval gun BL 15 inch Howitzer

Coastal artillery	QF 4 inch naval gun Mk I – III BL 6 inch Mk VII naval gun BL 9.2 inch gun Mk IX–X RML 9 inch

Mortars

Grenade launchers

Smoke and chemical weapons

Railway guns

Anti-aircraft guns

Foreign weapon designs
in British Empire Armies use

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