Big guns by Tower Bridge
HMS Belfast
HMS Belfast is the only surviving example of a big gun armoured warship built for the Royal Navy in the first half of the 20th Century. It is also the first ship to be preserved for the nation since Nelson's flagship HMS Victory.
Both of theforward gun turrets are now trained onto a target 12.5 miles away in north-west London - the Scratchwood Motorway Services Area on the M1.
Four 6-inch Mark XXIII Triple Gun Turrets
Each of these heavily armoured turrets weighs 175 tons and had a crew of 27 men working in each gun turret house. A well-trained crew could be expected to fire 8 rounds a minute from each gun. A further 22 men worked in the Shell Rooms and Magazines, well below the ship's waterline in the most heavily protected of all the ship's compartments.
Command and control
The turrets were controlled from one or both of the two armoured Director Control Towers and were originally equipped with large optical rangefinders. From 1942 onwards targets were normally tracked by radar. A mechanical computer calculated the gun elevation and training required to engage the target accurately.
The shells
The 6-inch shells had a mass of 51 kg. Mechanical hoists raised the shells, with the cordite charges which propelled them, to the gun house. There they were rammed into the gun breeches by hand. The guns could be used against targets at sea or bombard enemy positions on land and had a maximum range of about 22 km (14 miles).
Submitted by: Joanne Lonsdale, 19 January 2007
