The BL 4-inch gun Mark VIII was a British medium-velocity wire-wound naval gun introduced in 1908 as an anti-torpedo boat

Torpedo boat

A torpedo boat is a relatively small and fast naval vessel designed to carry torpedoes into battle. The first designs rammed enemy ships with explosive spar torpedoes, and later designs launched self-propelled Whitehead torpedoes. They were created to counter battleships and other large, slow and...

 gun in smaller ships whose decks could not support the strain of the heavier and more powerful Mk VII

BL 4 inch naval gun Mk VII

The BL 4-inch gun Mk VII was a British high-velocity naval gun introduced in 1908 as an anti-torpedo boat gun in large ships, and in the main armament of smaller ships...

 gun.

Mk VIII History

The gun succeeded the QF 4 inch Mk III

QF 4 inch naval gun Mk I - III

The QF 4-inch gun Mks I, II, III were early British QF naval guns originating in 1895. They all had barrels of 40 calibres length.-Naval service:The gun was intended to be a more powerful alternative to the 3-inch QF 12 pounder gun....

, whose 25-pound shell had been considered insufficiently powerful for its intended role. The BL Mk VIII fired a 31-pound shell. It armed the following warships :

• HMS Swift
  HMS Swift (1907)
  HMS Swift was a unique destroyer leader designed and built for the Royal Navy prior to World War I, another product of Admiral "Jackie" Fisher's relentless quest for speed...
  
   laid down 1905
• Tribal-class destroyers
  Tribal class destroyer (1905)
  The Tribal or F class was a class of destroyer built for the Royal Navy. Twelve ships were built between 1905 and 1908 and all saw service during World War I, where they saw action in the North Sea and English Channel as part of the 6th Flotilla and Dover Patrols.-Design:The preceding River or E...
  
   from Saracen
  HMS Saracen (1908)
  HMS Saracen was a Tribal class destroyer of the Royal Navy launched in 1908 and sold in 1919. During the First World War she served in the North Sea and the English Channel with the 6th Destroyer Flotilla.-References:...
  
  (1908) onwards.
• Beagle-class destroyers
  Beagle class destroyer
  The Beagle class was a class of sixteen destroyers of the Royal Navy, all ordered under the 1908-1909 Programme and launched in 1909 and 1910...
  
   of 1909
• Acorn-class destroyers
  Acorn class destroyer
  The Acorn class was a class of twenty destroyers of the Royal Navy all built under the 1909-1910 Programme, and completed between 1910 and 1911...
  
   of 1910
• Acheron-class destroyers
  Acheron class destroyer
  The Acheron class was a class of twenty-three destroyers of the British Royal Navy, all built under the 1910-11 Programme and completed between 1911 and 1912, which served during World War I. A further six ships were built to the same design for the Royal Australian Navy as River-class destroyers...
  
   of 1910
• River-class destroyers
  River class torpedo boat destroyer
  The River class was a class of six torpedo-boat destroyers operated by the Royal Australian Navy. Three were ordered for the Commonwealth Naval Forces in 1909; two were built in the United Kingdom, while a third was partially built, disassembled, then transported to Australia for reassembly...
  
   (Australia) of 1910.

The gun was succeeded in its class from 1911 by the QF 4 inch Mk IV

QF 4 inch naval gun Mk IV, XII, XXII

The QF 4-inch gun Mk IV was introduced in 1911 as a faster-loading light gun successor to the BL 4 inch Mk VIII gun, and was the main gun on most Royal Navy and British Empire destroyers in World War I.-Mk IV gun:...

.

In World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 many guns were used to arm merchant ships.

Mk XI submarine gun

A Mk XI variant was adapted to arm submarines :

• K-class submarines
  British K class submarine
  The K class submarines were a class of steam-propelled submarines of the Royal Navy designed in 1913. Intended as large, fast vessels which had the endurance and speed to operate with the battle fleet, they gained notoriety, and the nickname of Kalamity class, for being involved in many accidents....
  
   laid down 1915

See also

• 10.5 cm SK L/40 gun
  10.5 cm SK L/40 gun
  The 10.5 cm SK L/40 The 10.5 cm SK L/40 The 10.5 cm SK L/40 (SK - Schnelladekanone (quick-loading cannon) L - Länge (with a 40-caliber long barrel) was a German naval gun that was used in World War I and World War II.-Description:...
  
   Approximate German equivalent, firing slightly heavier shell
• List of naval guns

External links