Fort Siloso: The Guns of Singapore - Twin 6 Pounder QF Gun
A Twin 6 Pounder QF Gun at Fort Rodd Hill, Vancouver Island, Canada
The Twin 6 Pounder QF (Quick Firing) Gun had its origins in the 1920s. The Royal Artillery Committee was tasked with investigating the possible development of a new QF Gun for defence against torpedo boats. These were small fast craft, ideal for raiding harbours, so an effective quick firing gun capable of laying down heavy fire against them was necessary.
The Westwood Works of Peterborough, England, submitted a design for such a gun in 1925. This consisted of two 6 Pounder QF Guns with Semi-automatic Breeches housed in a three sided metal shield with a roof. The whole assembly was mounted on a Cradle attached to a pivoting Pedestal Mounting.
Trials of the gun commenced in 1928, and the gun was eventually accepted for service in 1934. It was 1937 before the first production gun, the ‘Q.F. 6-PR. 10 Cwt Mark 1’ on a Mark 1 Mounting, entered service. This gun was mounted at an AMTB Battery in Singapore.
Pre-WWII, the Twin 6 Pounder armed the Changi Outer (Palm), Pulau Sejahat, and the Berhala Reping AMTB Batteries. Post War, they armed OSO at Fort Siloso, Batu Berlayar, and Berhala Reping.
The Gun
Diagram of the Gun Barrel
The guns were constructed from steel, and weighed 9 cwt 1 qr 24 lb (480 kg). The barrel was rifled with 24 grooves. The gun body was fixed to a platform and mounted on a Mark I Mounting, capable of all-round traverse. The complete gun assembly and mounting was bolted to a Holdfast in the emplacement floor. The Holdfast consisted of ten bolts buried vertically in the concrete floor. Each bolt being 34·8 inches (88·4 cm) in length.
Two Ammunition Trays were attached to the platform, one each side of the gun body. The platforms were pivoted so that ammunition was always at the correct angle for the loading team. Each tray could carry 36 rounds of ammunition, stacked pyramid fashion. Because the gun could fire so quickly, additional ammunition would be held on Ammunition Trolleys, each carrying 36 rounds. These trolleys were on a curving track running around the top of the emplacement.
The gun mounted at Siloso after the war had been modified in the light of experience. It was modified so that as well as engaging sea targets, it could also be used in an anti-aircraft role.
Ammunition
Ammunition was Fixed QF. It comprised a primer and a propellant charge in a brass case to which was attached the projectile (shell) and fuse. The complete unit being called a ‘Cartridge’ or ‘Round’.
The shell was filled with H.E. and was made from forged steel. It weighed 6 lb 4 oz 48 dr (2·85 kg). The shells could be fitted with a tracer element if required. This would enable the flight of the shell to be followed visually.
A full charge of 1lb 6oz 3 dr (0·63 kg) of cordite propellant gave the gun a range of 5150 yards (4709 metres) at an elevation of 7·5°. A reduced charge of 13 oz 4 dr (0´375 kg) was also available. This gave a range of 3,900 yards (3566 m).
Gun Detachment
- Safety Officer: He could stop the gun firing should a target towing boat drift into range.
- No.1: The gun commander. He sat to the right of the gun barrels, and had a viewing telescope. He operated the gun traversing gear. His telescope could compensate for any deflection of shot required.
- Automatic Sight: On the left of the guns. This man controlled the elevation of the gun. His telescope was fitted with a Tidal Arc Lever. This lever adjusted the telescope for the height of the tide, and is calibrated for the height of the tide, above and below mean sea level for the particular gun. The sighting of any coastal gun is affected by the height of the tide, and an adjustment needs to be made for this.
- Direction Sight: on the right of the Platform. Controls the deflection required.
- Loaders: One for each gun. His task was to receive the cartridges form the handler behind him and push it firmly into the breech. A cartridge was placed under his arm, left or right, depending on which gun he was loading. He grasped the cartridge and inserted it into the breech.
- Handlers: One for each gun. He took a cartridge from the tray and placed it under the Loader’s arm, ensuring that it did not fall. The Loader then grasped the round with his free hand and thrust it into the gun’s breech. As might be imagined, the moves were carefully choreographed, and practiced to obtain the highest possible speed consistent with safety and accuracy.
- Ammunition Train: Further men were required to bring cartridges from the magazine and stack them on the Ammunition Trolleys ready for use.
The gun was capable of a rapid traverse, and despite being hand-loaded, the gun could achieve a rate of fire in excess of of 72 rounds a minute when served by a well drilled gun crew. The guns shields were fitted with a powerful extractor fan on the roof, to remove the build up fumes which would otherwise affect the gun crew.