Underground on Mount Faber are several concrete lined rooms. They are not really particularly well known, but they have often been visited by the inquisitive/explorers. These rooms are sometimes incorrectly referred to as being bunkers. However, bunkers they are not. This subterranean complex, built in 1936, was an integral and important part of Faber Fire Command. Its title was the Faber Fire Command Fortress Plotting Room.
A Fortress Plotting Room was where information about naval targets was received from Fortress Observation Posts, plotted and the required information extracted and then acted on. There were two Fortress Plotting Rooms in Singapore. The other was Changi Fire Command Fortress Plotting Room. In addition to the Fortress Plotting Rooms, Counter Bombardment gun batteries each had a Battery Plotting Room, which received information from the relevant Fortress Plotting Room and their respective Battery Observation Posts. There was also a Plotting Room in the Combined Battle HQ at Fort Canning.
The Counter Bombardment batteries were; Johore & Buona Vista 15 Inch Batteries, Connaught & Tekong 9·2 Inch Batteries, and the Sphinx 6 Inch Battery. The remaining gun batteries were classed as being Close Defence Batteries, and as such did not require plotting rooms.
In Penang, there were plotting rooms for the Batu Maung and Auchry Batteries.
Fortress Plotting Rooms contained a Range-finding Exchange (telephone), Fortress Plotters to track shipping targets on charts, Fall-of-Shot Indicators, Fire Direction Table, Ballistic Correction Calculators and other equipment to collate incoming information about the type of target and its range, speed and course.
LEFT: Sydney, NSW. 1944. Members of the North Head Battery, Sydney Fortress Area at work on a firing calculator in the Plotting Room:
Photo: Australian War Museum.
The Fall of Shot Encoder enabled the Fortress Plotting Room to take fall of shot observations from two Fortress Observation Posts and convert them into Clock Code.
Australian coast defences made extensive use of the Women’s Services to work in the plotting rooks and observation posts. This released men for service elsewhere.
Faber Fortress Plotting Room had two Fortress Plotters. Plotting Rooms had their own telephone exchanges to enable rapid communications to the Fire Command, Observation Posts etc. The telephone switchboard was not enclosed or in a separate room. This allowed the Plotting Officer in the Plotting Room to supervise all connections made. People staffing the plotting room would wear a head and breast telephone, the ‘hands-free’ phones of the day.
The Combined Battle HQ, Faber Fire Command and Fort Connaught plotting rooms certainly still exist. There is good evidence that the Tekong Battery Plotting Room still exists as well.
Buona Vista Battery Plotting Room
Almost certainly there in the KINS Camp. The entrance is sealed off.
Changi Fire Command Plotting Room
Almost certainly remains hidden in Changi Air Base on Changi Hill, between the masts and the golf club to the west.
Johore Battery Plotting Room
I've never managed to get an accurate fix for this, but if my thoughts about location are correct, it still may be there.
Sphinx Battery Plotting Room: Possibly destroyed by building work.