QF 5.25 inch / 50 naval gun

The QF 5.25 inch Mark I gun was the heaviest dual-purpose gun used by the Royal Navy . Although it was a less than completely successful design Fact|date=July 2008, it saw extensive service during the Second World War.

Design

The QF (quick-firing) 5.25 inch was designed to be a dual-purpose naval gun, for use against ships and aircraft. Combining the secondaries and heavy anti-aircraft armament would allow a significant savings of weight for the "King George V" class of battleships, which were originally intended to meet the Washington Naval Treaty limit of 35,000 tons. The gun fired an 80 pound shell, considered the largest that a gun crew could handle easily enough to give the rate of fire needed for anti-aircraft use.A class of anti-aircraft cruisers, the "Dido" class, was also designed using the gun as the main armament. As matters turned out, however, the gun was slow in many respects, one of them being rate of production. Only 267 were ever built, and not enough were available when the first "Didos" were launched for the full complement of ten guns. (Priority was given to the battleships.) When it was realized that the 5.25 was less valuable against aircraft, it was decided to keep the main armament at eight guns for a second batch of anti-aircraft cruisers.

Service

The dual mount turret proved too heavy to track quickly enough to engage the higher-speed aircraft of the Second World WarFact|date=July 2008. The cramped gunhouse also reduced the rate of fire from the designed twelve rounds per minute to eight or nineFact|date=July 2008. These problems rapidly made themselves felt in the loss of Force Z, and the Battle of CreteFact|date=July 2008.

The gun had a maximum surface range of 23,400 yards, and the 80-pound shell was well suited for use against destroyers and small cruisers. However, the gun was used on several occasions against heavier ships, most notably against the German battleship "Bismarck".

In 1944, VT-fused shells for the gun became available, making the gun significantly more effective against aircraft.

The mounting was improved and the fire control upgraded for the installation on HMS "Vanguard", which would prove to be the last battleship ever built. However, "Vanguard" never saw action.

Ship Classes

Ships with QF 5.25 inch Mark I guns:
*"King George V" class battleships
*"Dido" class cruisers
*HMS "Vanguard"

Popular Media

Author Alistair MacLean set his first novel, HMS Ulysses, on a fictional later-"Dido" class cruiser. In the book, MacLean described the 5.25 gun as "equally effective against surface and air targets". This opinion is not shared by the majority of naval historians.Fact|date=June 2008

See also

*QF 4.5 inch naval gun , the Royal Navy's medium-calibre dual-purpose gun.
*5"/38 caliber gun, the main US Navy dual-purpose gun during World War II.

References

*"Nelson to Vanguard: Warship Design and Development 1923-1945" by D.K. Brown
*"British Naval Guns 1880-1945 No 14" article in "Warship Volume VIII" by John Campbell
*"Jane's Battleships of the 20th Century" by Bernard Ireland