Vickers quad ship mounted machine guns
The formidable weapon pictured aboard a Royal Navy warship is the quadruple-mounted Vickers .50-inch Mark III, a close-range anti-aircraft gun created to place an immense concentration of bullets into the path of an attacking aircraft. Developed between the wars and widely fitted to British and Allied warships during the Second World War, it was essentially a greatly enlarged and more powerful version of the famous water-cooled Vickers machine gun.
Four guns were grouped on a single manually operated mounting, enabling one sailor to train and elevate the entire battery towards an approaching target. Each barrel was supplied by a 200-round belt carried in one of the distinctive ammunition drums visible in the photograph, giving the mounting 800 rounds ready for immediate use. Each gun could achieve a cyclic rate of approximately 600 to 700 rounds per minute, creating a combined theoretical rate approaching an astonishing 2,800 rounds per minute. Vickers claimed that the mounting could discharge all 800 available rounds in around twenty seconds, after which a well-trained crew could replace the four ammunition drums in about thirty seconds.
The guns were not arranged to place every bullet upon one precise point. Instead, they were adjusted to create a deliberately dispersed wall of fire approximately 60 feet wide and 50 feet high at a range of 1,000 yards. This gave the gunner a far greater chance of hitting a fast-moving aircraft, which could fly directly into a dense cloud of heavy bullets even when the aim was not exact. Armour-piercing and incendiary ammunition could damage engines, fuel tanks and lightly protected airframes, making the weapon especially dangerous against low-flying reconnaissance, bombing and torpedo aircraft.
The Mark III fired the British 12.7×81mm semi-rimmed cartridge, which must not be confused with the longer and more powerful American .50 BMG round used by the Browning machine gun. Water-filled jackets surrounding the barrels helped control the considerable heat generated during rapid firing, while the long conical flash suppressors reduced the bright muzzle flashes which might otherwise temporarily blind the crew during night action.
At the beginning of the Second World War, these distinctive quadruple mountings provided close-range protection aboard battleships, aircraft carriers, cruisers, destroyers and numerous smaller vessels. Against the slower and more lightly constructed aircraft of the inter-war years, the weapon appeared to offer an impressive defence. Wartime aircraft, however, rapidly became faster, stronger and better protected, and the British .50-inch cartridge increasingly lacked the range and destructive force required to stop a determined attacker before it released its bombs or torpedoes.
The quadruple Vickers was gradually replaced by the much harder-hitting 20mm Oerlikon cannon, although thousands remained in service and continued protecting Royal Navy ships throughout the war. Twin power-operated versions were also carried by motor gunboats and motor torpedo boats. Although eventually overtaken by more powerful weapons, the Vickers .50-inch Mark III remains one of the most striking naval anti-aircraft mountings of the period. When all four barrels opened fire together, it unleashed an extraordinary storm of steel, sending hundreds of heavy bullets skywards within seconds and creating a tremendous wall of defensive fire around the ship.
