The BL 8 inch gun Mark VIIIMark VIII = Mark 8. Britain used

Roman numerals Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, eac ...

to denote Marks (models) of ordnance until after World War II. Hence this was the eighth model of BL 8-inch naval gun. was the main battery gun used on the

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

cruiser A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several operational roles from search-and-destroy to ocean escort to sea ...

s,A more accurate term is "Treaty Cruiser", as the term heavy cruiser was only formally defined at the time of the London Naval Treaty of 1930. However, all the 8-inch gun cruisers introduced as a result of the 1922 Washington Treaty were what became known as "heavy cruisers". in compliance with the

Washington Naval Treaty The Washington Naval Treaty, also known as the Five-Power Treaty, was signed during 1922 among the major Allies of World War I, Allies of World War I, which agreed to prevent an arms race by limiting Navy, naval construction. It was negotiated at ...

of 1922. This treaty allowed ships of not more than 10,000 tons

standard displacement The displacement or displacement tonnage of a ship is its weight. As the term indicates, it is measured indirectly, using Archimedes' principle, by first calculating the volume of water displaced by the ship, then converting that value into wei ...

and with guns no larger than to be excluded from total tonnage limitations on a nation's

capital ship The capital ships of a navy are its most important warships; they are generally the larger ships when compared to other warships in their respective fleet. A capital ship is generally a leading or a primary ship in a naval fleet. Strategic i ...

s. The 10,000 ton limit was a major factor in design decisions such as turrets and gun mountings. A similar gun formed the main battery of Spanish cruisers.Campbell 1985 p.389 In 1930, the Royal Navy adopted the BL 6 inch Mk XXIII naval gun as the standard cruiser main battery in preference to this 8-inch gun.Whitley 1995 pp.96–127

Description

These guns, 50 calibres long, were

built-up gun A built-up gun is artillery with a specially reinforced barrel. An inner tube of metal stretches within its elastic limit under the pressure of confined powder gases to transmit stress (mechanics), stress to outer cylinders that are under tension. ...

s which consisted of a wire-wound tube encased within a second tube and jacket with a

Welin breech block The Welin breech block was a revolutionary stepped, interrupted thread design for locking artillery breeches, invented by Axel Welin in 1889 or 1890. Shortly after, Vickers Vickers was a British engineering company that existed from 1828 ...

and hydraulic or hand-operated

Asbury mechanism An Asbury Mechanism opens and closes the breech of heavy artillery for reloading with a projectile and bags of propellant. It was widely used for naval artillery of the world wars and similar coastal artillery and railway guns. The device was inv ...

. Two cloth bags each containing of

cordite Cordite is a family of smokeless propellants developed and produced in Britain since 1889 to replace black powder as a military firearm propellant. Like modern gunpowder, cordite is classified as a low explosive because of its slow burni ...

were used to fire a projectile. Mark I turrets allowed gun elevation to 70 degrees to fire high-explosive shells against aircraft. Hydraulic pumps proved incapable of providing sufficient train and elevation speed to follow contemporary aircraft; so simplified version of the Mark II turrets with a maximum elevation of 50 degrees were installed in . Each gun could fire approximately five rounds per minute. Useful life expectancy was 550 effective full charges (EFC) per barrel.

Naval service

The following ships mounted Mk VIII guns in 188-tonne twin turrets. The standard main battery was four turrets, but ''Exeter'' and ''York'' carried only three to reduce weight and formed the separate ''York'' class.Lenton & Colledge 1968 pp. 36–39 * heavy cruisers : 13 ships ** ''Canarias''-class heavy cruisers : 2 ships * ''York''-class heavy cruisers : 2 ships

Coast defence guns

Six single guns capable of elevating to 70 degrees were installed as

coastal artillery Coastal artillery is the branch of the armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications. From the Middle Ages until World War II, coastal artillery and naval artillery in the form of ...

in the

Folkestone Folkestone ( ) is a coastal town on the English Channel, in Kent, south-east England. The town lies on the southern edge of the North Downs at a valley between two cliffs. It was an important harbour, shipping port, and fashionable coastal res ...

Dover Dover ( ) is a town and major ferry port in Kent, southeast England. It faces France across the Strait of Dover, the narrowest part of the English Channel at from Cap Gris Nez in France. It lies southeast of Canterbury and east of Maidstone. ...

area during the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

Ammunition

File:BL8inchSAPKMkIBNTShell1943Diagram.jpg, File:BL8inchHENavalShellDiagram1934.jpg, File:428 Battery setting 8 inch shell fuzes WWII IWM TR 564.jpg,

Shell trajectory

Range with 256 lbs. (116.1) SAPC with MV = 2,725 fps (831 mps)

Surviving examples

* A gun from HMAS ''Australia'' outside the

Australian War Memorial The Australian War Memorial (AWM) is a national war memorial, war museum, museum and archive dedicated to all Australians who died as a result of war, including peacekeeping duties. The AWM is located in Campbell, Australian Capital Territory, C ...

, Canberra

Notes

References

Bibliography

* * *

External links

* Tony DiGiulian
Britain 8"/50 (20.3 cm) Mark VIII
* Terry Gander
Twentieth century British coast defence guns
{{DEFAULTSORT:BL 08 inch Mk 08 gun Naval guns of the United Kingdom Coastal artillery 203 mm artillery World War II naval weapons of the United Kingdom Military equipment introduced in the 1920s