Behold! The mighty Gun 1 at Napier of Magdala Battery stands before you. This location has long been strategically important. It protects the entrances to the main commercial harbor and the Royal Naval Dockyard in Rosia Bay. HMS Victory anchored in this bay for repairs after the Battle of Trafalgar in 1805. It then carried Admiral Lord Nelson’s body back to England.
Gun 1 is the best-preserved example of an early “Supergun”. It was designed and manufactured in Newcastle-upon-Tyne by Sir W.C. Armstrong in 1870. It was nicknamed “The Rockbuster”. Four were originally made for the Italian Navy. The British Government became alarmed. Their Mediterranean bases might be defenseless against long-range bombardment. They commissioned two guns each for Malta and Gibraltar.
Only two of these guns survive today. One resides in Malta and the other here in Gibraltar at Napier of Magdala Battery. The second gun in Gibraltar was at Victoria Battery. That site is now the Gibraltar Fire Station. Aspects of the underground infrastructure of that gun position still survive. The Fire Brigade of Gibraltar uses them for training.
The Gun 1 you see at Nelson’s Anchorage was originally at Victoria Battery. It was moved here after the gun split during firing. The gun could originally fire a round every four minutes. Lieutenant Colonel Ogilvie’s detachment reduced this time to two and a half minutes. This possibly contributed to the splitting of the original barrel.
The 100 Ton Gun battery at Nelson’s Anchorage was constructed between 1878 and 1884. It was built on the site of the old 2nd and 3rd Rosia Batteries. The cost was £35717.00. It is named after the governor, Lord Napier of Magdala. It remains a monument to Victorian artillery and technology.
This gun has a steel barrel encased in layers of wrought iron. This created a massive bulk in the breach area. It represented the Zenith of heavy engineering in the Victorian era. The barrel comprised a toughened steel tube in two parts. It was forged and tempered in oil, with a steel ring over the joint. Sixteen wrought-iron coils were shrunk on successively.
The 17.72 inch Rifled Muzzle loader, or 100 Ton Gun, has a barrel more than 32 feet long. It could fire a shot up to 8 miles. It was an amazing weapon in its time. It was the largest gun that needed to be muzzle loaded. A hydraulic system powered by steam was required to carry out the loading and firing.
A steam engine pumped water into the bottom of a well. This forced an 85-ton piston up the shaft. This weight compressed the water and provided hydraulic pressure to move the gun. Achieving sufficient pressure could take a minimum of 3 hours. This was adequate for an era when most ships still had sails.
Each gun required a crew of 35 men. After the initial steam was built up, the crew could fire the gun every four minutes. It took 450 lbs of black prism gunpowder packed into silk cartridges to propel the 2000 lb shell. The shell left the muzzle at 1540 feet per second. The cartridges were made of silk because this was almost entirely consumed by the explosion.
The 100 Ton Gun was muzzle loaded using hydraulically powered ramrods 45 feet long. The barrel was turned to one chamber to receive its silk-cased charges of black prism gunpowder. It then traversed 180 degrees to the opposite chamber to receive a shell.
The 100 Ton Gun had a 150-degree field of fire. It could engage a target up to eight miles away. This would have covered the Bay of Gibraltar and the Spanish mainland towns of San Roque, Los Barrios, and Algeciras. More conservative estimates put the gun’s maximum range at around five miles. The official record lists the accurate range limit as only 6500 yards.
The inside of the barrel was rifled with 28 twisting grooves. This imparted rotation to the projectiles in flight and increased their accuracy. Large copper discs, called gas checks, stopped exploding gases leaking past the projectile.
In 1863, Captain William Paliser invented a method of casting shot. This produced a brittle, but extremely hard tip. A shell from the 100 Ton Gun could penetrate 24.9 inches of wrought iron.
Though much would have been familiar to a gunner in Nelson’s Navy, it contained many revolutionary features. It was fired with a platinum wire heated red hot by electricity from a battery. Information to aim the gun was conveyed to a telephonist by range-finders higher up the Rock.
Gun 1 stands as a testament to a more violent time. It reminds us when the Rock was unbreachable. It stands as a testament to the supremacy of the British naval fleets.