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Gun Club Hill Barracks in Kowloon was silenced in this way by British guns on Hong Kong island.
The Fortress System
By the 1930s the operation of batteries had become immensely sophisticated and complicated, difficult for a layman to understand. The old 19th century arrangement of individual battery range and position finders was improved by a new arrangement known as the Fortress Range Finding System. Under this system the range of vision and of precision was greatly extended by a series of what were known as Fortress Observation Posts to cover targets within range of the guns. These transmitted bearings and ranges gained from observation to a central Fortress Plotting Room where the target, such as an enemy vessel, was tracked on a chart known as a Fortress Plotter. The co-ordinates of the target were then calculated or computed on a mechanical device known as a predictor which made allowance for the time in flight of the shell and the movement of the vessel assuming it had not realised it had been observed and taken evasive action by changing course. The co-ordinates were then telephoned or telegraphed to the individual batteries which then possessed all the information necessary to engage the enemy, even though the target might be so far away as to be invisible to the Battery Commander. The data could also be relayed directly to the guns where it was displayed on electrically operated dials.
In Hong Kong as part of reorganisation and modernisation of the Hong Kong defences a Fortress Range Finding system was developed consisting of three Fortress Plotting Rooms at Stanley Fort, Mount Davis and Tytam Gap, also ten Fortress Observation Posts all connected to two Fire Commander's Posts which in turn, were connected to the Commander Fixed Defences who had his Coast Artillery Headquarters in the underground Operational Headquarters in Victoria Barracks known as Fortress HQ, nicknamed the "Battle Box". The Fortress Plotting Room at Stanley Fort is located in an underground bunker below an old Signal Station, Block 3, opposite the Officers' Mess. Remains of a plotting table and predictor still can be found inside.