The History of Andalucia

The Rockbuster

The Rockbuster 100 Ton Gun, Gibraltar

In 1870 Sir W.C.Armstrong at Newcastle Upon Tyne designed and built 4 guns for the Royal Navy. Two went to Malta and two to Gibraltar to secure the anchorages at these strategic naval bases. Today only two remain, one each in Malta and Gibraltar. In their day they were unique, their statistics are staggering.

Each weighed 100.2 tons and had a barrel 32.65 feet long and a bore of 17.72 ins. Of that length 30.25 feet was rifled which greatly increased the accuracy of the gun. The shot fired weighed 2000 lbs and the charge was 450 lbs of black prism gunpowder. This gave a muzzle velocity of 1,540 feet per second, which is just over 1,000 miles per hour, well in excess of the speed of sound and a range of 8 miles. When it reached its target the shell could penetrate 24.9 ins of iron. The gun could fire one round every four minutes and required 35 men to serve it. To cope with the massive weights involved in loading and traversing, each gun had a steam engine that fed high-pressure steam to a hydraulic accumulator. It took 3 hours to generate the required head of steam. Not surprisingly the gun at Gibraltar was nicknamed ‘The Rockbuster’. They were the largest muzzle loading guns ever built, the new breech loading system was introduced soon after their manufacture which effectively made them obsolete.

One gun was placed at Victoria Battery, now the site of the Fire Station, the second at Napier, Magdala battery. The gun now at Napier is actually the gun from Victoria, the original having split its barrel during a test firing. It is only when you stand on the battery next to the gun that its size is fully realised. Alongside it stands a diminutive anti aircraft gun dating back to 1939.

In 1902 the Inspector General of Artillery visited the battery to see the gun fired. Unfortunately only the ‘tube’, the small charge used to fire the main charge, exploded. The misfire drill was carried out to no avail. The only option left was to draw the shot. After waiting thirty minutes, just in case the main charge did fire, the call went out for volunteers to be lowered down the barrel to fasten the shell extractor to the nose of the shell some 25 feet inside. A small, thin gunner was volunteered and duly lowered into the barrel. He successfully attached the extractor and both he and the shell were safely removed. He was immediately promoted to the rank of bombardier.

The last firing of the ‘Rockbuster’ took place in 2002 to mark the Calpe 2002 Conference between Gibraltar and Malta. Today visitors to the interpretation centre and the gun marvel at this monument to Victorian steel and steam engineering from an era when Britain really did Rule the Waves.