The Mark II 6 Inch QF Battery built on Mount Siloso was operational by September 1900. The two Mark II Guns on Pedestal Mountings represented a step change on the two 7 Inch RML Guns they replaced. The firepower of the fort was significantly increased by them. The 6 Inch QF Gun had a range of 12,000 yards (10,973 metres) and was capable of a rapid rate of fire when served by an experienced team of gunners. Seven Rounds per minute could be expected from a well trained gun crew. The 6 Inch Gun in its various forms was destined to become the mainstay of coast artillery batteries throughout the British Empire. It saw service until 1956.
The Emplacement before and after restoration.
Today, the No.1 6-Inch QF Gun Emplacement on Mount Siloso is not seen as it was when in service at the end of the nineteenth and the beginning of the twentieth centuries. During the upgrade of the Fort in the 1930s, the Gun well was filled in, and a Position Finder was built on it. Restoration work carried out in 1994 sadly meant the removal of the Position Finder, but the emplacement was not restored to its original condition.
A dummy 6 Inch Gun Barrel on a tripod is over the No.2 Emplacement. When mounting a gun, the Gun Mounting and Cradle would be installed in the gun well first. In the case of this emplacement, Sheers would probably have been used to mount the Barrel. These are explained in the section about Parbuckling.
The Siloso QF battery would only remain atop Mount Siloso for a few years before being moved to replace the 9·2 Inch Gun further down the hill. The 9·2 Inch Emplacement and Magazine underwent significant rebuilding to accommodate the 6 Inch QF Guns. The plan of the new emplacement on the left is drawn from the Fort Record Plan dated 1912. The magazine below is shaded. In the 1930s, this emplacement was rebuilt for two Mark VII 6-Inch BL Guns. Post WWII, there were some further minor modifications to enable the emplacement of two Mark 24 6-Inch BL Guns. These modifications are what can be seen today.
The new emplacement would give the guns an improved arc of fire to the west. Once moved downhill, the 9·2 Inch and 6 Inch QF Batteries across the harbour entrance at Fort Pasir Panjang were retired. A new, more powerful Mark X 9·2 Inch BL Gun Emplacement on Mount Imbiah was brought into service to replace the old Mark IVs at Siloso and Pasir Panjang.
Three 6-Inch QF Batteries were constructed to defend Keppel Harbour; Fort Siloso, Fort Connaught (The Guns here were later removed to Fort Silingsing on Pulau Brani), and Fort Pasir Panjang.